The large eddy simulation model is used to simulate the three-dimensional sinusoidal oscillating jet in the cross flow environment. The differences of motion characteristics and dilution law between the non-oscillating jet and the oscillating jet in the cross flow environment were analyzed, and the influence of oscillating parameters of the jet was discussed. The results show that the shape of oscillating jet is obviously different from that of non-oscillating jet in the cross flow environment, and its trajectory is bent, showing an obvious “intermittent effluent cloud” phenomenon. Compared with the non-oscillating jet, the impact height and bending degree of the oscillating jet are significantly increased, and the mixing with surrounding water is intensified. With the increase of oscillating amplitude, the impact height and minimum dilution of the jet increase. In general, the oscillating jet is beneficial to the dilution of pollutants in the cross flow environment.