A sterilization method and system are disclosed, where a sterilization cycle includes at least an evacuation step of a sterilization chamber is performed one or more times and provides that: the chamber is isolated from the condenser； at least a steam generator is operated to inject a predetermined amount of heated steam directly into the condenser； the steam in the condenser is cooled and condensed, so as to reduce its volume and accordingly lower the pressure within the condenser to below that present in the sterilization chamber； and the condenser is placed in communication with the sterilization chamber to perform an evacuation.
