The optical properties of doubling the measurement accuracy using the cube-corner retroreflector which is applied to laser straightness measurement are analyzed in theory. The effects on straightness measurement are analyzed for the cube-corner retroreflector with angle errors, surface errors, yaw, pitch and roll. The analysis results are proved by experiments. The analysis results indicate that this work has provided the theoretical basis for analyzing error and error compensate during the laser straightness measurement with cube-corner retroreflector.