For geometric distortion caused by squint imaging of a zoom aerial camera, an automatic simultaneously correction method for both squint trapezoidal distortion and nonlinear distortion of the zoom lens was proposed. Based on the same geometric type between straight line and its ideal projection image, the one-parameter division model was adopted to estimate the distortion coefficient and the distortion center coordinates at different focal lengths by an optimization searching method of variant step length. The effects of focal distance change on the distortion coefficient and distortion center coordinates were researched, then the lens's distortion was corrected to satisfy the ideal pinhole imaging model. By introducing the position and attitude of airplane and the pointing azimuth of the optical axis for the camera, the oblique aerial images specified in the camera frame were georectified into the mapping frame. The pixel intensity after coordinate transformation was resampled to obtain orthorectified images without the lens distortion and squint distortion. The correction experiments were performed for the distortion patterns captured under various focal lengths, positions and attitudes and the actual aerial zoom oblique images, and the results show that this method effectively and accurately corrects the geometric distortion of images. The Root Mean Square Error (RMSE) of image geometric correction is about 2 m when the flight height is 2 500 m with the position and attitude measurement precision given in this article.The precision satisfies the requirements of the follow-up image mosaicing. It concludes that the method is more efficient, easy to realize in automation and has great signifiance for promoting aerial image mosaicing precision, implementing fast positioning and real-time tracking of moving objects.