本文论述了定义物理量的基本要求并对平衡压力下了定义.然后,简略地证明了平衡压力的稳定条件以及燃烧室压力与平衡压力的近似关系.对于侧面燃烧装药的固体火箭发动机,在稳定条件下,燃烧室压力-时间曲线上只有少数特殊点处于平衡状态工作,而大量的其它点处于准平衡状态下工作. This paper discusses the basic requirements of the definition of physical quantities and defines the equilibrium pressure.Then, the stability conditions of the equilibrium pressure and the approximate relationship between the pressure and the equilibrium pressure of the combustion chamber are briefly demonstrated.For the solid rocket motor with side-burning charge, Conditions, only a few special points on the pressure-time curve of the combustion chamber work in equilibrium, while a large number of other points work in a quasi-equilibrium state.