Abstract: Objective A coastal low water model with high precision has important application value.Aiming toexploit the characteristics of multi-source and precision difference between different tidal data for con-structing coastal low water models,a method based on multi-source tidal data is presented in the pa-per.By utilizing multi-source tidal data,such as tidal gauge data and low water data calculated basedon satellite altimetry data,interpolation method of tidal data is modified by assigning a weight todifferently sourced data,depending on the precision information,thus the coastal low water model isconstructed considering the precision difference between different source data.Experimental resultsdemonstrate that the proposed method can utilize multi-source tidal data and improves the quality ofcoastal low water models,which can meet the demand for special applications such as extracting lowtide lines.