[Purpose/significance] The OpenAPI service system is developed for sharing and integrating the CADAL digital resources. The libraries of CADAL member universities can use the OpenAPI service to effectively integrate their local resources with the related CADAL digital resources, and provide new mashups for the readers. Besides, provided with the OpenAPI, readers could retrieve and utilize related CADAL digital resources conveniently, which would enhance their experience quality. [Method/process] The OpenAPI service system is designed and developed based upon the metadata of CADAL digital resources. With the further development of the open technology framework, the technical team provides a standard application program interface to facilitate the developers to access the metadata of CADAL digital resources. The format of search results could be JSON or XML, and these formats can be easily processed by programs developed for integrating and presenting the digital resources.[Result/conclusion] The libraries of CADAL member universities can use the CADAL OpenAPI interface to integrate the digital resources; meanwhile, the readers can easily retrieve the related CADAL digital resources when they search resources on third-party platforms. The development of OpenAPI system does not only reveal, render and utilize the CADAL digital resources, but facilitates readers to acquire and use the CADAL digital resources.