This　paper　presents　a　novel　experimental　approach　for　confirming　that　spherical　mirror　of　a　laser　tracking　system　can　reduce　the　influences　of　rotation　errors　of　gimbal　mount　axes　on　the　measurement　accuracy.　By　simplifying　the　optical　system　model　of　laser　tracking　system　based　on　spherical　mirror,　we　can　easily　extract　the　laser　ranging　measurement　error　caused　by　rotation　errors　of　gimbal　mount　axes　with　the　positions　of　spherical　mirror,　biconvex　lens,　cat＇s　eye　reflector,　and　measuring　beam.　The　motions　of　polarization　beam　splitter　and　biconvex　lens　along　the　optical　axis　and　vertical　direction　of　optical　axis　are　driven　by　error　motions　of　gimbal　mount　axes.　In　order　to　simplify　the　experimental　process,　the　motion　of　biconvex　lens　is　substituted　by　the　motion　of　spherical　mirror　according　to　the　principle　of　relative　motion.　The　laser　ranging　measurement　error　caused　by　the　rotation　errors　of　gimbal　mount　axes　could　be　recorded　in　the　readings　of　laser　interferometer.　The　experimental　results　showed　that　the　laser　ranging　measurement　error　caused　by　rotation　errors　was　less　than　0.1　mu　m　if　radial　error　motion　and　axial　error　motion　were　within　+/-　10　mu　m.　The　experimental　method　simplified　the　experimental　procedure　and　the　spherical　mirror　could　reduce　the　influences　of　rotation　errors　of　gimbal　mount　axes　on　the　measurement　accuracy　of　the　laser　tracking　system.