Abstract: Laser gyro can not be used as a metrological standard due to the problems of zero drift and traceability. To give full play to its superior high-precision angle measurement performance, this paper introduces its application in the measurement field in detail, redefines the performance parameters that can characterize the laser gyro goniometer more intuitively, and gives the definitions of “scale factor” and “bias” corresponding to “scale factor” and “zero drift” in the laser gyro. The performance parameters of the laser gyro goniometer, such as scale factor nonlinearity, stability and scale factor temperature sensitivity, scale coefficient temperature sensitivity, bias repeatability, stability and bias temperature sensitivity are tested experimentally, and the calibration method suitable for the laser gyro goniometer is given. Finally, a method to remove the linearity error is proposed to solve the problem of on-line measurement of laser gyro goniometer. The experimental results showed that the angle measurement error introduced by linear fitting error is less than 0.05'', and the zero division error of laser gyro goniometer is ±0.5'', which provides an effective on-line measurement method for measuring angular position error.