Abstract:In order to make full use of historical data and reduce the investment of tide gauge in the surveying area,without reducing the surveying accuracy,the technicians calculate the fixed-point tide level in the sea by using the historical data of synchronous tide measurement and adopting the method of astronomical tide level plus residual water level.The concepts in technical requirements are explained in detail,and this paper uses the historical data of synchronous tide measurement to calculate the water level of the fixed-point tide gauge based on curve comparison transmission method.The accuracy of the calculation is verified and discussed,and finally the conclusion is drawn.