Abstract: Three improvement measures for improving the accuracy of the subway tunnel through survey was adopted in a practical case and analyzed the observation data. The results demonstrated that these measures could improve the accuracy of the subway tunnel through survey.The improvement measures are as follows:The CORS is adopted as satellite positioning control network starting basis. Suspension atilizes three wire method and double measuring method to increase the check condition by connection surveying. The accuracy of the underground traverse with the high precision gyroscope and the detection of the nuclear underground wire is presented in the appropriate position.

Key words: breakthrough survey, accuracy, CORS, connecting triangle, gyroscopic orientation