The polarization characteristic of objects is an inherent characteristic, depending on the external and internal structure of targets as well as the incident angle. Therefore, the measurement of leaf moisture content was researched with polarization information. The research process was divided into the following five parts: Establishing the laser polarization imaging measurement system, calculating the polarization degree of targets, measuring the actual moisture content of leaf, establishing a mapping model between polarization degree and leaf moisture content, and validating the mapping model. According to the target and environment characteristics, the devices and steps of experiment can be chosen and adjusted. The polarization degree can be measured by the method of extracting grey-scale value of the image. Moisture gradient processing was used to measure the actual moisture content of leaf. The mapping models between polarization degree and leaf moisture content were established in the first to third orders based on statistical method. Their stabilities and predictive abilities were compared to analyze their applicable conditions, which provide a theoretic foundation of leaf moisture content measurement with polarization information. The result shows that the polarization degree increases progressively with the moisture content rising from 15%to 75%. The mapping relationship was obvious in case of the high moisture content, while it was insignificant in case of the low moisture content.