Abstract: The vertical degree（incline degree） measurement of fan tower tube in wind power plant is studied, and the high precision prism-free total station instrument is proposed to observe the vertical degree of fan tower tube, this paper discusses the observation methods and technical requirements under the condition of meeting the requirements of the code, and practices it through an engineering example, and verifies it by another method, and obtains reliable data results, therefore, the applicability and feasibility of this method are verified and summarized.