The invention discloses an optical measurement method and an optical measurement device for the five-degree-of-freedom rotation errors of a spindle. The optical measurement device comprises a precision-turned flange, four point laser generators, four CCD (Charge Coupled Device) cameras (CCD for short) and other fittings, wherein the flange is mounted on the end of the measured spindle. In the process of measurement, the flange is rotated along with the measured spindle, the four point laser generators emit four laser beams into the conical surface of the flange, and the laser beams are reflected by the conical surface and are then projected onto the four CCDs. When the spindle does not have rotation errors, the position of the light spot on each CCD is at the center of the CCD; and when the spindle has rotation errors, the positions of the light spots on the CCDs are changed. By capturing and subsequently processing the positions of the laser on the CCDs, the invention can measure theradial play (Delta x, Delta y) and axial play (Delta z) of the spindle and the deflection errors (Epsilon x, Epsilon y) of the spindle around the X axis and the Y axis. The method has a simple structure, the equipment cost is low, and the invention can carry out non-contact on-line measurement on the five-degree-of-freedom rotation errors of the spindle, and has higher measurement speed.