The invention discloses a volume-variable storage room connected with a security door. The storage room comprises a right channel, a right door frame, a right door, a left door frame, a left channel and a left door. The right channel is installed in a right wall opening, the right door frame is installed at the right end in the right channel, the right door is connected with the right door frame through a hinge, and a right door lock is arranged on the right door. The left door frame is fixed to the left end of the left channel, the left door is connected with the left door frame through a hinge, and the left door is provided with a left door lock. The left of the right channel and the right of the left channel are connected in a sleeved mode to form the storage room, and the volume of the storage room is changed by sliding the left door frame of the left door. The left door is the antitheft door capable of being communicated with a room. The storage room is reasonable in structural design, the application range of a common room gate is widened, convenience is brought to production and life, and the storage room is suitable for being popularized and promoted in the urban and rural housing industry.