It is known that a constant injection mass is a criterion for measuring the thermal efficiency of diesel engines. In this study, the effects of the injection pressure on the spray structure after wall impingement are investigated under the condition of a constant injection mass. Experiments are performed in a constant volume combustion chamber using a high-pressure common-rail injector with a single-hole nozzle. A high-speed camera and Schlieren visualization setup are used to capture the behavior of liquid- and vapor-phase impingement spray, respectively. Variation laws for the radius, height, and area of impingement spray in both the liquid and vapor phases are obtained by analyzing the images captured in these experiments.