To study the effect of packaging methods on sterilization efficacy of infectious waste sterilized by vertical pressure steam sterilizer, verify its biological safety, and provide basic data for formulating technical guidelines for treatment of infectious hazardous waste in hospital laboratories in China. Methods Two vertical pressure steam sterilizers in infectious waste disposal room of microbiology laboratory of a hospital were selected as observation objects, experimental bacteria was Bacillus thermophilus bioindicator (ATCC6767), experimental material included glass test tubes (cotton ball sealing), glass plate and plastic bags for medical waste, experiment were divided into non-packaging group, open packaging group for medical waste plastic bags and sealing packaging group for medical waste plastic bags, statistical analysis of experimental results was performed through treatment effect test and safety verification test. Results Culture result of biological indicators showed that sterilization effect could all be achieved when bioindicators were in non-packaging group sterilized at 121℃ for 20 minutes and 132℃ for 5 minutes,in open packaging group at 121℃ for 60 minutes, and in sealing packaging group at 121℃ for 105 minutes. Whether the plastic bags were open or sealed, setting the temperature at 132℃ for 5 minutes sterilization could melt plastic bags of medical waste. Conclusion Infectious wastes packaged in the open package at 121℃ for 65 minutes sterilization and in sealed package at 121℃ for 110 minutes sterilization is recommended, sterilization procedure at 132℃is not recommended.