Cloud platform is found to be an appropriate way to meet the need to improve the performance of information sharing among manufacturing companies. However, there is still a huge gap to be bridged for collaboration among different stakeholders due to interest conflict or distrust. Especially when the whole system is firmly controlled by centralized third parties. Blockchain is a technology based on cryptography, distributed system and consensus mechanism, which is meant to be a critical method used in value convergence to strengthen connections among enterprises and effectively solve trust issues to a certain extent. Obviously it would benefit for platform performance to elevate operational transparency as well as immutability, which are precisely the comprehensive properties of blockchain. This paper proposes a blockchain-based cloud platform manufacturing services composition architecture and elaborates the business collaboration system in detail. Manufacturing resources on the cloud platform are in the form of services to be accessed by any registered users in the system. The blockchain stores and broadcasts transaction and matches results generated in the core cloud services layer. Furthermore, a quality of service (QoS) attribute model is built to evaluate the service composition problem and genetic algorithm is adopted to solve it. Finally, a simulation experiment is presented as the application of proposed system.