The precision and uniformity are important parameters for evaluating metrological radial grating. A set of automatic detection system is designed for the detection of uniformity and precision of the reflective metrological radial grating. This system adds the reflective reading system on the basis of the original angle tester. The signal is transmitted to the computer by the acquisition system, and the location information is passed to the computer by a tiny encoder. Then the data were processed by the LabVIEW, to complete the automatic error detection and process control. Finally, the test results will be printed out and keep on a file. After the actual test on reflective metrological radial grating with 32768 lines. The relative precision error of the grating is ±0.75″, the uniformity error is less than 4.2%. The system was fast, high precision and stability. It simplifies the traditional test equipment and debugging steps, and realizes the automation of measuring the precision and uniformity of the circular grating.