Abstract: Previous studies on the wave-current interactions in the third generation wave models only focus on the current-induced changes in propagation velocity and direction of wave groups and the associated wave refractions, but ignoring the changes in wave energy spectra. In our  study, numerical experiments are conducted based on the MASNUM-WAM (Key Laboratory of Marine Science and Numerical Modelling Wave Model), in which the wave-current interaction function is adopted, and the effects of horizontal wave-current interaction on numerical simulation of both wave spectra and wave parameters are elucidated. It is concluded that the outputs of the wave-current interaction source function can be influenced by various factors, such as the magnitude and direction of the horizontal field gradient of ocean currents, water depth, and development status of wind waves, causing differences arising from both the simulated significant wave heights and spectrum peak directions. In fact, those differences can be very small in real-world current fields, with consideration of long-distance propagation, however, the wave-current effects on spectrum peak directions may significantly change the propagation patterns of swells.