The medium volume diameter （MVD） of droplet is one of the most basic and important parameters of an icing wind tunnel, and the accuracy of MVD measurement affects the study of icing performance of aircrafts. This paper presented a simple method for measuring water droplet diameter by laser particle size analyzer, which can be applied in small icing wind tunnels. The calibration of MVD is carried out based on rotating multi-cylinder method. According to the icing accumulation of rotating multi-cylinders, the rime ice accumulation on a two-dimension rotating cylinder is numerically simulated. In combination with successive approximation method, the software for the parameter analysis of rotating multi-cylinder measurements is programmed. Calibration results agree well with the measurements. The results indicate that the calibration method is effective for the rapid measurement of the MVD.