Abstract: Aiming at the problem that the time exposure error of image acquisition is not uniform due to the unstable flight speed of UAV photography, a large-scale image free control method for UAV is proposed. First of all, this paper discusses the analysis of the camera lens distortion error model and the problem that the exposure of UAV is not synchronized due to the exposure delay. Then, the exposure delay model is introduced into the traditional GPS auxiliary beam method adjustment model, and a GPS auxiliary beam method adjustment method with the exposure delay is proposed. Finally, the effectiveness of this method is verified by an engineering example. The experimental results show that this method can be used in the UAV when the control point is involved, thus it can meet the accuracy requirement of 1∶500 large scale mapping.