Diurnal and semi-diurnal tides in the Taiwan Strait and its adjacent areas are calculated by using a two-dimensional finite-difference model. Compared with data of more than 20 observation stations around the Taiwan Strait, the model-produced results agree quite well with those of previous researches using observational data from coastal tidal gauge stations. According to the results, the co-tidal and co-range charts are given. Furthermore, the characteristics of 8 major tidal constituents have been uminated respectively. The result shows that： （1） The tide motion can be attributed to the interaction between the degenerative rotary tidal system in the north and the progressive tidal system in the south. （2） The southward and northward tidal waves of semi-diurnal tide converge in the middle of the Taiwan Strait while the diurnal tidal waves propagate southwestward through the Taiwan Strait and the Luzon Strait. （3） The maximum amplitude of semi-diurnal tides exists at the area between the Meizhou Bay and Xinghua Bay, and that of diurnal tides appears in the region to the east of the Leizhou Peninsula, （4） The patterns of co-tidal and co-range charts of N2, K2 and P1, Q1 tidal constituents are similar to those of M2, S2 and K1 O1 tidat constituents, respectively
