Optical brackets are important parts of a terahertz (THz) experiment system. It is of great significance to improve the experimental accuracy by studying the reflection properties of the common optical brackets and taking proper measures to reduce reflection impacts. In this paper, a variety of common optical brackets, such as a square filter fixed bracket, a triangle block, two stainless steel connected rods and several rod bases et al., are measured in the reflection experiments by using contrast measurement method. The reflectivity of the optical brackets with incident angles of 45° using 2.52 THz laser have been obtained approximately. It can be inferred from the results that the smooth stainless steel connecting rods have a relatively higher reflectivity. The reflectivity of the rod with a diameter of 25 mm is about 43%. For the painting rod base with uneven surface and a diameter of 25 mm, the reflectivity is 0.62%. The reflectivity of the diamond-shaped stripe area of the lift rod base is only 0.35%.