Abstract: The present invention discloses an office soundproof compartment and a mounting method thereof, and the compartment comprises a lower compartment body, an upper compartment body and a compartment door. The lower compartment body comprises a seat, telescoping columns and a plurality of lower compartment plates. The upper compartment body comprises top plates and a plurality of upper compartment plates; the top plates are connected to the telescoping columns and can move in synchronization with the telescoping columns and the top plates are maintained in extended or retracted state relative to the lower compartment body; one end of at least one of the upper compartment plates is connected to the lower compartment body, and the other end is detachably connected with the top plate when the top plate is in extended state, which can save packaging costs, occupy less transportation space, help handling and can be mounted simply, conveniently and quickly.