The invention discloses a side surface fast mounting mechanism for a photovoltaic bracket. The side surface fast mounting mechanism comprises an inclined plane pressure block, an inclined plane base, a connecting piece, a bolt and a nut, wherein hanging hooks are arranged on the two sides of the upper part of the inclined plane base, and the inclined plane base is mounted on the connecting piece through the hanging hooks; the inclined plane pressure block is placed on the inclined plane of the inclined plane base, a stepped hole is formed in the inclined plane pressure block, and a spring is placed in the stepped hole; a waist-shaped hole is formed in the position of the inclined plane base, which corresponds to the connecting piece; and the bolt sequentially penetrates through the connecting piece, the inclined plane base, the inclined plane pressure block and the spring, and the upper end of the bolt is connected with the nut. The side surface fast mounting mechanism disclosed by the invention is simple in structure, low in cost and fast and convenient in mounting process; a spring structure is adopted for realizing fast mounting of the inclined plane pressure block in a preset position, so that the inclined plane pressure block can be conveniently and reasonably clamped into a groove of a guide track, the spring in a locked state can be finally compressed into a countersunk hole, and the reliability and aesthetics in locking can be ensured; the square-neck bolt and the nut are adopted, thereby effectively preventing the following rotation and improving the mounting efficiency; and a side-surface fast mounting piece base can realize adjustability in height during the mounting process, thereby solving the problem that a roof is uneven during actual mounting.