Based on the prime focus optical system applied on the polaxis telescope, the primary mirror support design and analysis, the primary mirror alignment and test, corrective lens assembly design and alignment to system alignment and test were detailed discussed. The finite element method was used to analysis the primary mirror support, the centering facility was used to test the optic axis concentricity, and the collimator was used to test system image quality. A general method was obtained that is suitable for the prime focus optical system alignment and test. The primary mirror surface figure RMS is 0.0428λ after alignment, and the corrective lens assembly coaxial error achieves 12.4″. The energy centralization method was adopt to evaluate system image quality, and star point 80% energy concentrate degree was in 4×4 pixels on target area, which achieved design requirements. The results indicate system design is reasonable and alignment method is proper. This method also can be used to another prime focus optical system alignment and test.