Regarding the traditional star photography method in the field accuracy assessment of photoelectric theodolites, which is easily restricted by spatiotemporal conditions, and the comprehensive flight calibration method that consumes a lot of resources, research has been conducted on new methods for field accuracy assessment. By integrating Real-Time Kinematic (RTK) technology with small unmanned aerial vehicle (UAV) technology, a high-precision dynamic positioning system has been constructed. This enables high-precision dynamic localization of airborne targets and completes the joint testing for static and dynamic accuracy assessment of electro-optical theodolites in field conditions. It effectively addresses the drawbacks of traditional star photography methods and comprehensive flight calibration techniques, while also offering advantages such as low cost, simple operation, lightweight portability, and rapid deployment and retrieval. Actual experimental data met the requirements for field assessment of photoelectric theodolites. The analysis results indicate that RTK technology combined with small UAV technology can provide a new means for field accuracy assessment of photoelectric theodolites, with good application prospects.