Abstract: The harmonic analysis of tides and tidal currents is a basic method for the analysis of ocean hydrological data, and the contradictory equations generated during the harmonic analysis are usually dealt with by means of the least square method. However, due to the limits of computing power and programming language in the past, the solving method of the contradictory equation was made more complicated, which is not good for marine science and technology workers to master and use. By taking the method for quasi-harmonic analysis of tidal current data observed in short period as the example, the solving method of contradiction equation generated during the tidal current quasi-harmonic analysis is discussed, the previous method for the solving of normal equation is deduced and explained and a more concise matrix representation method is put forward. The advantages, disadvantages and characteristics of the two methods are compared, finding that the matrix method is even more suitable for programmatic analysis and calculation on a computer. On this basis, the daily tidal current data of three weeks observed in the sea area near Dafeng of Jiangsu Province are taken as the example for calculation and their harmonic constant, ellipse element and residual current are obtained by using the matrix method. The tidal current data of the same period are also forecasted and the forecasted results can match well with the original data.