The flame structure and combustion characteristics of wall-impinging diesel fuel spray were investigated on a high-temperature high-pressure constant volume combustion vessel. The ambient temperature (Ta) was set to 773 K, and the wall temperature (Tw) was set to 523 K, 673 K, 773 K respectively. Three different injection pressures (Pi) of 600 bar, 1000bar, 1600bar, and two ambient pressures (Pa) of 2 MPa, 4 MPa were applied. The flame development process of wall-impinging spray was measured by high-speed photography, which was utilized to quantify the flame luminosity intensity, ignition delay, and flame geometrical parameters. The results reveal that, as the wall temperature increases, the flame luminosity intensity increases and the ignition delay decreases. However, the wall temperature has a little influence on the luminosity intensity at the condition of Pa = 4 MPa and Pi = 1600 bar, which is probably because that the higher ambient pressure and injection pressure promote the atomization and evaporation of fuel,and counteract the effect of different wall temperatures. At the condition of Pa = 2 MPa, the flame height increases as the wall temperature increases, the ignition position is always observed in the wall jet region and the distance between ignition position and the axis of the spray decreases as the wall temperature increases. The region of highest luminosity intensity is observed in the head vortex region in all tested wall temperatures. At the condition of Pa = 4 MPa, the flame heights of different wall temperatures are nearly the same in the initial stage of combustion, while the flame height decreases as the wall temperature increases at the later stage of combustion. The ignition position is observed in the impingement region and the region of high luminosity intensity appears in the location near the wall region in all tested wall temperatures. As the injection pressure increases, the flame luminosity intensity decreases. The distance between ignition position and the axis of the spray increases as the injection pressure increases at Pa = 2 MPa, while the ignition position is always observed near the axis of the spray in all tested injection pressures at Pa = 4 MPa. Finally, it can be concluded that the change of the wall temperature mainly affects the flame luminosity and the ignition delay and the change of the ambient pressure mainly affects the flame height and the ignition position. For injection pressure, the change of that mainly affects the flame luminosity.