This study aimed to assess HIV/AIDS-related knowledge, sources and perceived need among senior high school students in China. A total of 2668 senior high school students aged 15.17-23.42 years participated in the survey. A self-administered questionnaire was used to collect information on HIV/sexually transmitted infection-related knowledge, sources and perceived information need. The results showed that levels of HIV/AIDS knowledge were distributed as follows: low for 6.8%, moderate for 29.6% and high for 63.7%. The most important information sources were, in rank order, TV/photographic recording (72.1%), school heath education curriculum (51.8%) and reading materials (45.7%). About half of the students, 46.3%, confirmed a need for more information and 87.8% of the sampled senior high school students communicated with others if he/she had problems related to HIV/AIDS. Strengthening and improving information sources, particularly its accuracy and comprehensiveness, would help in ensuring that adolescents obtained the HIV/AIDS health information they needed.