Abstract: In order to improve the adjusting accuracy of space telescope secondary mirror Stewart mechanism, the precision calibration is necessary. For the 6-PSS Stewart adjusting mechanism, first of all, the parameter calibration model was obtained by the kinematics and the least square method. Secondly, the usually cuckoo search based on simplex(SMCS) method was modified by use of VSA and limitation bounds algorithm to improve the global accuracy of optimization problem. The better calculation ability compared to SMCS was verified by the simulation results. Finally, to ensure the validity of the whole travel distance, a test data sampling process included six elements of position and orientation was planned. Experimental results show that the displacement error at the sampling point is reduced from the maximum 19.97m to 9.68m, and the angle error is reduced by a maximum of 123.84 to 8.86. Similar results are also shown with good accuracy at the non-sampling points, the proposed method based on the aforementioned model can effectively improve position accuracy of the secondary mirror adjusting mechanism, and the compensation results is efficient for the whole travel distance.