The invention belongs to the technical field of machinery manufacturing, and particularly relates to a controllable adjusting and measuring device of ball screw pretightening force and pretensioning amount. The pretightening force adjustment of screw nuts is achieved through three pretightening force devices which are of the same structure and are evenly distributed between the two screw nuts, each pretightening force device can conduct pretightening on the two screw nuts through tightening the nuts to press a spring, and the magnitude of the pretightening force can be measured in real time through a pull pressure sensor, so that the controllable adjustment of the pretightening force of the screw nuts can be achieved; the ball screw pretensioning is achieved by the method that tensile force is imposed to a separated mobile platform to drive a ball screw fixing supporting seat to move, and thus drawing force is generated to the ball screw, the pretensioning amount is measured through a dial indicator fixed to the end of the screw, and the magnitude of the drawing force is measured in real time through two pull pressure sensors fixed on the side face of the mobile platform.