The invention discloses a chair which comprises a chair surface, four legs and a sitting block. The four legs are arranged on the lower surface of the chair surface, and the chair surface can be supported by the legs; a center hole is formed in the center of the chair surface, and the sitting block is arranged in the center hole; a chair back is arranged on a side of the chair surface; a slide rail is arranged at a joint of the chair surface and the chair back; two sliders are arranged on the slide rail; the chair surface is divided into a left face plate and a right face plate; the left face plate is connected onto one slider by a screw; the right face plate is connected onto the other slider by a screw; the left face plate and the right face plate can be separated from each other along the slide rail; the left face plate and the right face plate can rotate around the screws. The chair has the advantages that the chair is provided with the sitting block, and storage spaces can be saved when the integral chair is used; the chair can be separated from the sitting block when required, accordingly, service requirements of multiple persons can be met, and the chair is easy to operate and is practical and convenient.