In order to achieve high accuracy measurement for non-landing vehicle-mounted photoelectric theodolite (NVPT) with continuous zoom optical system, a theoretical model of pointing error is presented. Starting with the working mode, the error source of the whole closed loop which affects the pointing error is analyzed. The measurement equation is derived using a coordinate transformation. The pointing error model is then obtained with the help of Monte Carlo method. The error of an NVPT prototype is measured, showing that the pointing error can be predicted accurately. A high precision NVPT with continuous zoom optical system is successfully designed and analyzed, with an accuracy of 11.9″ at azimuth and 10.9″ at elevation, when the optical focal length is set between 1 000 mm and 4 000 mm.