The most important condition for achieving laser gyro (LG) stable operation and high precision characteristics is to ensure the constancy of the laser resonator length, so that the ring laser generates on a single mode. Computer simulation of processes in the resonator length control system of the Zeeman LG allows predicting its operating time on a single mode with keeping high accuracy. In the paper, the method of computer simulation is considered, which enables instead of multi-hour long technological tests during production to conduct short tests and then use the obtained data to prognosticate further LG behavior by applying an approximating function. The algorithm for the computer implementation of this method and the results of experimental studies, which confirmed an excellent coincidence of the approximating function with the experimental dependence, are presented. With the application of the proposed method, a multiple reduction of the technological stage duration of LG production is achieved with getting the data for sorting LGs on their accuracy. This permits us to improve Zeeman LG production arrangement, matching it with the basic principles of lean production, such as eliminating useless procedures, reducing the duration of technological operations. © 2022 SPIE.