Abstract: Isoplanatic angle is one of important optical turbulence parameter which has played a significant role in the design of adaptive optics system and the analysis of compensation effect. An apodized mask with triple concentric annuluses was introduced, Measuring principle, measuring method and main specifications were introduced in this paper about the high precision isoplanatic angle. Next to the Xinjiang region, the measurement experiment of isoplanatic angle was carried out, and was compared with single ring isoplanatic angel measuring instrument. The results show that two sets of instruments measured such as isoplanatic angle trends are basically identical. The triple concentric mirror can better modulate the light intensity to match the weight demand of the isoplanatic angle measurement with altitude. The error of the fitting coefficient is small, and it can realize the high precision measurement of the isoplanatic angle.