The invention provides an adjusting mechanism for an inclined angle of a tablet personal computer. The adjusting mechanism for the inclined angle of the tablet personal computer comprises a ball head, an upper cover plate and a lower cover plate, wherein a ball socket is formed in the lower cover plate, the ball head is arranged in the ball socket, a through hole is formed in the bottom of the ball socket, a connecting rod can be connected with the ball head through the through hole, a press plate is arranged above the ball socket, and is used for pressing the ball head into the ball socket, the press plate is connected with the lower cover plate through an adjustable mechanism so that the degree of pressing of the press plate to the ball head can be adjusted, and the upper cover plate and the lower cover plate are assembled to form a support which is used for installation of the tablet personal computer. Due to the facts that the structure that the press plate presses the ball head into the ball socket is stable, and the upper cover plate covers the structure in a cooperative mode, the ball head can be effectively prevented from falling off, the ball head can be comprehensively pressed through the mode of cooperation between the ball socket and the press plate, the ball head can be better wrapped, the ball head can be stressed in an all-directional mode, the ball head can be evenly stressed, and the ball head, the ball socket and the press plate can achieve better functions; due to the fact that the ball head can be comprehensively wrapped, the ball head can be easily pressed and fixed after the ball head is rotated through the adjusting mechanism.