Abstract: Detonation propulsion system has the advantages of high thermodynamic efficiency and fast heat release, which gradually shows the trend of replacing traditional propulsive technology, and has broad application prospects in hypersonic air-breathing propulsion systems. For the propulsion system, the total pressure loss should be as small as possible. Studying the total pressure characteristics from the global solution domain of oblique detonation wave is beneficial to control the total pressure loss level in the conceptual design stage of the detonation propulsion system. In this paper, the formed and stable oblique detonation waves are focused, and simplified into a discontinuity with energy input. The total pressure loss of oblique detonation wave is studied by using the shock polar. Taking the normal Mach number before oblique detonation wave to represent the strength of oblique detonation, the relations of oblique detonation wave are derived. It is found that the law of the weakest shock wave strength of oblique shock is also applicable to oblique detonation wave. By using shock efficiency diagram, it is proved that the minimum total pressure loss characteristic of oblique detonation still exists, and it is further revealed that the minimum total pressure loss line will shift to a larger shock angle with energy input, and the symmetrical relation of total pressure loss is broken. In addition, the effects of the amount of input energy by combustion and the wedge angle inducing detonation on the minimum total pressure loss are also obtained. When the input energy is large and the wedge angle is small, the minimum total pressure loss point of oblique detonation wave will shift more easily to a large shock angle. Finally, according to the characteristics of the total pressure of oblique detonation, a simple design idea which can increase the theoretical upper limit of total pressure of the engine is presented. The law of total pressure of oblique detonation wave will provide conceptual design direction of oblique detonation engine.