To establish the vocational education personal learning account and achieve the traceability, query and conversion of learning results, the paper proposes a credit platform of vocational education chain. The technical characteristics of block chain decentralization, bookkeeping, asymmetric encryption, distributed, smart contract and consensus mechanism are used to construct the platform. In system design and system logic design, we focus on how to evaluate students more objectively, completely and accurately, how to make the platform more secure, public and shared, and how to make colleges, students and enterprises more trustworthy and prefer to use credit platforms. In view of the difficulties in the construction of credit platform nodes in polytechnic education chain, such as credit issuance and acquisition, credit query and so on, this paper puts forward some ideas and carries out prototype design. As a result, the credit platform is made more suitable for the development of educational alliance, collectivization, diversification and Internet +, open, shared and lifelong education.