The expression of misalignment aberration of off-axis reverse system is derived, and an efficient off-axis reverse system assembly and adjustment method is proposed, based on the vector aberration theory. Through the analysis, it is found that the off-axis system will not introduce new forms of aberration, but due to the aperture factor, compared with the coaxial system, several primary aberrations will be scaled, and the high order aperture aberration will be partially transformed into low order aperture aberration. The misalignment aberration expression is verified by the simulation of an off-axis-two-reverse system, using Zemax. The misalignment in the simulated alignment reaches the order of 10^-4mm. Finally, use the method to guide the assembly and adjustment of the actual off-axis-two-reverse system beam expansion system. The primary aberration reaches the order of 10^-4(λ=632.8nm), and the RMS value of the system reaches 0.04λ, which verifies the accuracy of the method.