Abstract: This paper systematically analyzed the height mean square error, and the height mean square error mainly depended on ranging error and angle measurement error. According to the following instances: the bridge pier height control of the Chengdu-Mianyang-Leshan passenger dedicated railway line, the repetition surveying and control extension of height control network in Niu-Lan-Jiang to Dian-Chi replenishment project, they all proved that trigonometric height measurement can replace leveling measurement in certain conditions, the precision can reach the requirements of four-grade-leveling measurement.