To optimize the layout of UAV (unmanned aerial vehicle) base station and improve the efficiency of 3D reverse modelling of engineering structures, a control parameter named BHR (breadth height ratio) was proposed and a total of 25 comparison sets were set up; then, an experiment was designed to effectively simulate the three-dimensional reconstruction scenario of actual engineering structures, comparing the errors of point positioning, movement trajectory, and linear change measurement under different comparison sets. The reasonable layout of base station was evaluated from two aspects: work efficiency and model accuracy. Finally, a three-dimensional reconstruction of a prefabricated steel frame structure was conducted to verify the effectiveness of the proposed optimal layout method in engineering applications. The results show that 25 comparison sets reveal similar patterns in the measurement of three types of features, that is, the error decreases with the decrease of BHR and observation distance. There is a significant difference in the error change rate of 25 comparison sets, with majority of comparison sets with a shooting distance > 0. 8 m showing a negative contribution. According to the modelling time, the most reasonable layout method is comprehensively evaluated as BHR = 0. 18 and H = H_eff/2, and it has been applied to practical engineering and achieved good results. The proposed UAV base station layout method can significantly reduce the modelling time while ensuring the accuracy of 3D reconstruction.