The invention relates to a coaxiality detection device for long and heavy shaft parts. The device comprises a base, clamping devices and a detection device, wherein the clamping devices are symmetrically arranged at two sides of the base; the detection device sleeves a workpiece and comprises a shaft sleeve and a rotating shaft sleeve; a dial indicator is arranged on the shaft sleeve and penetrates through a side wall of the shaft sleeve; a measuring head of the dial indicator is aligned with an inner side wall of the shaft sleeve; the dial indicator is fixed on the shaft sleeve; and a rotating handle is arranged on the rotating shaft sleeve. The coaxiality detection device for the long and heavy shaft parts has the beneficial effects that the measuring head of the dial indicator arrangedon the shaft sleeve is in contact with the surface of the workpiece in the rotating process of the shaft sleeve and indicates out an error; and a movable V-shaped block can move back and forth along sliding rails at two sides of the base and is used for positioning the shaft sleeve, so that the measuring head of the dial indicator is prevented from being tightly pressed on the surface of the workpiece due to the gravity in the rotating process of the shaft sleeve and the error is avoided.