The aim of this paper is to test the trajectory precision of the execution terminal of the industrial robot based on a non-contact laser tracing measurement technique. The target is found in terms of tracing mirror attached in measurement position. This method utilizes the linear motion units and photo detection units to trace the target actively. The measurement of the target coordinates are measured with the laser interferometer linear measurement module and the grating ruler. This system can achieve the trajectory measurement of the planar motion objects without contact in real-time condition and also possesses the high precision. The experimental work and calculation were performed in order to achieve the trajectory precision of the research.