A sterilization method for a liquid-prefilled ampoule is provided, which is utilized to place the ampoule in a retort sterilizer for sterilization. The sterilization method includes a two-stage constant-temperature constant-pressure process. In a first constant-temperature constant-pressure process, the ampoule has a state of internal and external pressure balance. In a second constant-temperature constant-pressure process, the ampoule is sterilized. With the sterilization method of the invention, yield of the sterilized ampoule can be increased.一種預充填液體的安瓶之滅菌方法，其是將預充填一液體之安瓶置於一滅菌釜內進行滅菌，該滅菌方法包括有兩階段的恆溫恆壓過程，於第一次恆溫恆壓過程，使該安瓶之內壓與外壓達到平衡；於第二次恆溫恆壓過程，使該安瓶進行滅菌，本發明之滅菌方法可提升安瓶滅菌後的良率。
