The invention discloses a coaxiality measurement device and method for long-distance non-contact shafts and belongs to the field of error measurement of precision machinery. The measurement device comprises a laser module, a four-quadrant detector module, a reference shaft, a to-be-measured shaft and an optical platform. The laser module mounted on the reference shaft and the four-quadrant detector module mounted on the to-be-measured shaft are rotated, information of the center and radius of a locus circle is formed through laser spot scanning of the four-quadrant detector module, the coaxiality error of the two long-distance non-contact shafts can be accurately, rapidly, simply and conveniently measured, the measurement device adopts a modular design concept, the laser module and the four-quadrant detector module are mounted in other precise machinery provided with the long-distance non-contact shaft structures, and measurement of the coaxiality of the long-distance non-contact shafts can also be realized.