To calculate the wave uplift force on a trestle-type wharf on a steep coast under working conditions of long-period waves and shallow water deformation，this paper takes the China-assisted wharf construction project in La Libertad Department of El Salvador as an example. Results of physical model tests and theoretical calculations according to relevant domestic and foreign code manuals are compared to analyze the wave uplift force on the superstructure. The following observations can be made from the results：1）The theoretical formulas work mostly for progressive waves，and those applicable to long-period plunging waves are rare in number；2）Considering steep coast topography，long period，shallow water deformation of waves，wave breaking，and other factors，cross-sectional physical model test is more in line with actual wave conditions，and the uplift force tested is more reasonable and accurate；3）The wave uplift force should be determined under comprehensive consideration of values obtained from physical model tests and theoretical formulas. The results are used in the optimization design of hydraulic structures，and they provide a reference for future wharf design under similar working conditions.