Like internet, connecting quantum computers together to build a full quantum network will enhance the ability to process quantum information. On-chip quantum memories can possess the essential functionalities in building a quantum network, including synchronizing a large number of quantum computers and implementing long-distance quantum communication. However, owning mainly to the constraints imposed by the micro-photonic structures themselves, on-chip quantum memories cannot satisfy the requirement for constructing the full quantum network for the incompatibility of their memory property and integration property. We here propose to build an on-chip quantum memory by using spatial-phase-mismatching effect in photonic crystal cavities. In this scenario, not only is the large orbital angular momentum of photonic crystal cavities utilized to realize photon-echo type memory, but also the light-matter enhancement of a photonic cavity is used to achieve a high-efficiency quantum storage.