The invention discloses a method for realizing content delivery based on a passive optical network. The method comprises the steps of 1, establishing a layered content delivery architecture based on a PON system, namely using the content delivery system of a single PON system as a content delivery module of an edge area, wherein the content delivery module of the edge area comprises two architectures, namely an OLT content delivery module and an ONU service module; 2, performing a content injection method and process, namely issuing a service strategy, wherein content injection comprises active injection and passive injection; and 3, performing a content delivery method and process. According to the method, through setting the content delivery module in OLT and ONU of the passive optical network, a two-stage content delivery architecture in the PON system, a storage and delivery strategy in the PON system, and a matching strategy among the PON system, an upper network, a content server and an upper CDN are made, thereby realizing the integral layered CDN architecture system, realizing network efficiency and improving user experience.