The invention relates to a locking mechanism of a position and posture adjustable visual tracking template, comprising a position adjustment mechanism and a posture adjustment mechanism, wherein a bottom plate of the position adjustment mechanism is fixedly connected with a slider; the slider is internally provided with a cavity in which a belt and a press block are located; a rod part at the upper end of the press block is externally provided with threads and extends out to be matched a tightening screw; a rod part at the upper end of the tightening screw extends out from a hole on a tightening screw cover and is fixedly connected with a tightening nut; a ball socket is formed between a ball sleeve and a ball tile of the posture adjustment mechanism; a ball head is located in the ball socket; the ball sleeve is fixedly arranged on the slider; ball hinge bolts are arranged at two sides of the ball sleeve and the conical surface at the end of the ball sleeve is matched with the conicalsurface at the lower end of the ball tile; and the visual tracking template is fixedly connected with the ball head. In the invention, the position and posture adjustment of the visual tracking template is realized through adjusting the position between the press block and the belt and adjusting a ball joint; therefore, the template can be well tracked by a visual system, the operation is convenient, the fixing manner is simple and convenient and the quality and the efficiency of the surgery are greatly improved.