The ambient gas flow fields of the free spray and flat wall-impinging spray were measured by using laser induced fluorescence-particle image velocimetry (LIF-PIV) technique in non-evaporating condition. The ambient gas velocity distribution and gas mass flow rate into the spray were analyzed. The droplet flow velocity and vorticity of free spray and impinging spray were measured by particle image velocimetry (PIV) technique, the correlation of spray droplet flow and ambient gas flow under the free spray and impinging spray conditions was studied. The effects of impinging distances (30 mm, 40 mm) and injection pressures (100 MPa, 200 MPa, 300 MPa) were taken into account. Comparing with the free spray, the impinging spray restricts the ambient gas flow at the specific timing; however, showing the same or higher ambient gas flow as function of the penetrating length. Furthermore, the increased vorticity intensity implies that the turbulent mixing and mixture formation inside the spray tend to be improved. The increased fuel injection pressure effectively improves the ambient gas flow and the vorticity intensity of the spray. The effect of injection pressure on the improvement of ambient gas flow becomes moderate under the impingement condition. The shorter spray wall impinging distance restricts the increase of the spray volume and the ambient gas mass flow rate.