The image quality of an astronomical telescope degrades in observations if the misalignment of optical elements exists. The degredation is more severe in astronomical systems with large aperture and fast focal ratio. To solve this problem， the paper proposes an active alignment method for routine observations of telescopes. The proposed method here aims to maintain the image quality by quasi-real time corrections on both the position and attitude of the telescope secondary mirror via the computation of star images. Considering the ellipticity of the star images in multi-field-of-view， the proposed method uses the particle swarm optimization to iteratively solve the misalignment of the telescope optics， so as to correct the lower-order aberrations induced by the misalignment. The simulation in the paper is carried on with 1.6 m multi-channel photometric survey telescope， proving that the residual error of misalignment of the secondary mirror is less than 1%， within the tolerance range. Further simulation and experiment are carried out on the Three Antarctic Survey Telescopes （AST3-3） for the verification， proving that the proposed method is able to precisely solve the misalignment of the telescope optics.