In the present study, a numerical wave tank is developed to simulate the nonlinear wave-current interactions based on High Order Spectral （HOS） method. The influences of current on wave focusing are investigated by use of numerical model. The current is assumed to be constant in space. Focused waves with different amplitudes and frequency spectra are simulated with and without current. The focused wave characteristics, such as surface elevation, the maximum crest and frequency spectrum, with different current are compared. The results show that the opposing current increases the maximum crest and the energy transform during wave focusing process, and vice versa for the following current.
