The invention relates to a two-factor slow-release system based on POC and mesoporous nanospheres. The two-factor slow-release system based on the POC and the mesoporous nanospheres is a composite film, specifically a polycitric acid-1,8 octanediol ester film loaded with mesoporous silicon dioxide microspheres. The invention further provides a preparation method of the film and a medicine-loadingsystem using the film as a release carrier. In the composite film, the hollow mesoporous microspheres have a high medicine-loading rate and the POC can be degraded, and the two-factor slow-release system formed by the two can improve the durability of the medicinal efficacy and has an important application value in controllable transportation and release of medicines, dyes, cosmetics, and sensitive reagents such as a growth factor and the like.