Abstract: The squint SAR(synthetic aperture radar) high resolution imaging formation and geometric correction method based on the diving model were studied. The general three-dimensional geometric model was founded based on the SAR movement mode. The equivalent squint range model was derived from this general geometric model and the echo signal expression was given based on this range model. According to the signal's characteristic, burst work mode was adopted in diving SAR, and a modified ECS(extended chirp scaling) imaging algorithm was utilized to form high resolution image. The imaging formation flow chart and four ECS phase compensation factors were presented. According to the range equation and Doppler positioning equation, geometric correction calculating expressions corresponding to ECS algorithm were derived. The computer simulation results illuminated that the modified ECS algorithm could be used to form high resolution image for diving model SAR and squint SAR, also geometric distortion could be calibrated with this correction method.