The first reliable information about the castle can be found in the charter from 1349, written by the Lords of Rýzmburk, and serves as an evidence about an existing castle residency. The Lords of Osek, also called Lords of Rýzmburk, were the first provable holders of Bečov domain. The castle was built in the first half of 14th century at the latest. The research on wooden construction components provides us with reliable data (the oldest component dates back to 1352).
During the first phase of development, a keep (a bergfrit) was erected, which served as a defensive tower, and a residency was built in a place of today´s Pluh´s Palace. Later (after 1352), a tower was constructed, which was supposed to serve as a new residency, but the plans were changed and thus a chapel was built in that unfinished tower, through its three floors. The altar side was not orientated towards East, but, in regard of the predisposition, towards North. In the chapel, there is a unique collection of mural paintings in al secco technique (painted in dried plaster) dating back to 1360. Around 1400, the building was damaged, probably during an earthquake. The walls cracked. After 1356, a representative residential tower was erected - a French type - donjon (one of the biggest donjons in Czech Republic). The walls in the private rooms of the master were decorated with late Gothic paintings. The residential and the chapel towers were connected by ramparts.
In 1495, Pluhs of Rabštejn got possession of the domain and because they developed tin mining in the area, they had the castle rebuilt considerably - the interiors of the donjon were adjusted, the oldest building behind the keep was rebuilt in a Rennaissance style (these buildings are called Pluh´s Palace until these days), the donjon and the chapel tower were connected with a wing, which served for formal and representative purposes (feasts, celebrations).
In 1624, the domain was acquired by Questenberks. The castle served as a siege for the imperial garrison until 1648, in that year, the garrison was captured by General Königsmark, who conquerred the town and the castle.
During the Thirty Years´ War, the castle was already used for agricultural purposes. The change in use of the castle buildings brought extensive repairs in 1641.
In 1656, after the experience from the Thirty Years´ War, the Questenberks added a bastion above the moat to increase defensive efficiency. This bastion was then incorporated into the chateau tower in 18th century, and became a part of this newly built mansion.
In 1752, Jan Adam Questenberk died and the domain was inherited by Dominik Ondřej Kounic ml. (a nephew of his second wife).
The domain was bought in 1813 by Friedrich August Beaufort-Spontin, who imagined the future of his noble family in Austria, a place that was not affected with the revolutionary movement like the one in France and Belgium.
The Shrine of St Maurus was bought from the ecclesiastical authorities by his son Alfred Beaufort-Spontin. Alfred had the domain repaired in 19th century, he envisaged to remodel the medieval castle into a Romntic chateau, which had to be connected to the Baroque Chateau according to a concept created by Josef Zítek. Due to financial demandingness, only the Chateau Chapel was redecorated.
After 1840, the remains of medieval fortification were blasted off and this act was possibly a reason for a partial damage caused to the Castle Chapel. The medieval Castle was used as a granary at that period.
The agricultural purpose of the building left most of the decoration and accessories of the medieval castle preserved (historic furnishings - a built-in cupboard and window seats dating back to the constructive period of the castle, Gothic ceiling joists with floral paintings, flamboyant Gothic portals, roofing dating back to 1641 and 1720). As compared with other castles in Czech Republic, the Bečov Castle is rarely preserved in its medieval features.
The grand-son of Alfred, Heinrich and his wife Adelheid Sylva-Tarouca built a large landscape park, which used to be compared to a famous park of Průhonice.
Beaufort-Spontin family collaborated with Nazi regime during the II World War and according to Presidential Decrees from 25th October 1945 about the confiscation of enemy belongings and estates, issued by Edvard Beneš, the family had to leave the domain.
Later on, the Chateau served as a school and the Pluh´s Palace and the medieval Castle had to become a museum. In 1969, the whole domain was controlled by the Office for Historical Monuments in Pilsen and the reconstruction works begun. In 1996, the Baroque Chateau became accessible to public, an exhibition of West Bohemian Gothic had been organized, then it was replaced with an exposition of accessories from the confiscated collections of the former holders. This exposition is now placed on the second floor and the first floor is dedicated to the unique Romanesque Shrine of St Maurus.