The utility model discloses a rolling bearing pre-tightening adjusting device having a detection function. The adjusting device is composed of a hand wheel, a lead screw, a support, a supporting frame, a nut, a clamping mechanism and a detection mechanism, the clamping mechanism is capable of clamping a transmission shaft on which a bearing which is detected is installed, the hand wheel is rotated, when a required pre-tightening force is displayed on a data display instrument of the detection mechanism, numerical values on three dial indicators in the detection mechanism are read, difference values compared with initial values are figured out, a mean value of the difference values is calculated and obtained, the axial clearance of the bearing which is detected under the pre-tightening force can be obtained, parameters such as the radial clearance of the bearing which is detected can be calculated and obtained through the bearing dimensions, and finally the bearing pre-tightening force is adjusted according to the parameters such as the axial clearance or the radial clearance obtained through calculation. According to the rolling bearing pre-tightening adjusting device having the detection function, by measuring the axial clearance of the bearing, an appropriate adjusting part or adjusting amount is selected by one time, so that the bearing pre-tightening amount is satisfied accurately, and the bearing is more efficient and accurate to assemble.