The invention discloses a method for evaluating car matching quality through virtual assembling. The method mainly comprises a part scanning step, a virtual assembling step, a gap and flatness analyzing step and an adjusting and optimizing step, and comprises the following specific steps: after scanning parts and carrying out virtual assembling, taking a theoretical car body as the reference, analyzing flatness and gaps of each part of the virtually assembled car body according to the theoretical gap and flatness requirements, making a part measurement report and a flatness and gap measurement report of n assembly, providing candidate virtual assembly schemes for solving the problem by adjusting different assembly positions of parts, and selecting an optimal virtual assembling scheme from the candidate virtual assembling schemes so as to achieve the optimal matching quality. According to the method disclosed by the invention, the normal measurement, analysis and evaluation of the matching quality can be realized; the rapid adjustment and the evaluation of multiple schemes can also be realized; furthermore, important characteristic lines and small rounded corners can also be evaluated; in addition, the method has the advantages of being short in implementation period and low in cost.