Upon the fairness, security and flexibility problems of traditional digital rights management, we proposed a blockchain infrastructure service based DRM platform with high-level credit and security, in which we first proposed a Blockchain as a service (BaaS) architecture to decrease the complexity and difficulty of building up a blockchain-based business model, the BaaS infrastructure transparently provides easily-developed user interface to implement all core functions such as genesis block creation, consensus mechanism definition, node initialization and running, wallet management, address management, blockchain explorer et al. Then based on the BaaS infrastructure we proposed a blockchain-based DRM platform with high-level credit and security for Content provider (CP), Service provider (SP) and customers. We designed the blockchain as infrastructure service for DRM business model and provided core content rights information storage in blockchain for tamper-resistant copyrights protection from being misused, and the content consumers can use blockchain-based digital assets for content consumption payment, and the platform can help the content demandside and supply-side trading and the blockchain recorded the trade data as tamper-resistant evidence. Evaluation experiments manifests the proposed scheme is reliable and secure, and provided an efficient methodology for blockchain application business model implementation.