Optical tests for the off-axis aspherics in optical processing and optical assembling were researched and the effect of adjustment errors on the wavefront aberration was analyzed. By taking an off-axis aspherics with the radiu of 10 000 mm,quadratic surface coefficient of -1,diameter of 500 mm and the lateral displacement of 425 mm for an example, the physical model and mathematical model to describe the relationship between the adjustment parameters and the wavefront aberration were estabished. The adjustment parameters included the pitch and high-low errors, beat and off-axis distance errors,and the rotating parameters around the secondary optical axis. The matlab software was used to simulate the influence of the wavefront aberration on the adjustment errors.Then, the experiments were performed to examine the simulation results.It shows that the the simulation results are well concident with the experiment ones, which proves the theory model in correct. The obtained results are also suitable for the test and alignment of other off-axis aspherics.