Cross-domain collaboration of government services is a new governance model, which has been spawned by the combination of digital transformation of government and cross-domain governance. This model is aimed at achieving the value goal of governance of government services. However, due to the different specific business and functions of each government department, each department has an independent data management system, and each information system has diverse storage, complex data formats and different business processes. As a result, sharing and utilizing the heterogeneous data between departments in a safe and reliable way has become a challenging research problem. Traditional government data sharing usually adopts a centralized sharing mode, which is prone to a series of issues such as data privacy leakage, departmental authority problems, and single point of failure. To address this issue, this paper proposes a government data sharing scheme that combines attribute-based encryption and blockchain. Firstly, an access control policy is formulated by the data owner to restrict the attributes of data requesters. Subsequently, fine-grained access control as well as key update in secure data sharing is achieved by using subset overlay technology, which is combined with linear secret sharing to achieve complete hiding of the access policy. The inter planetary file system distributed network is used to store the ciphertext after symmetric encryption to relieve the storage pressure of the blockchain system. Finally, the hash of the retrieved data ciphertext is re-encrypted using the Keccak algorithm to achieve data integrity verification. Security analysis and experimental analysis show that the proposed scheme can meet the requirements of secure sharing of government data in terms of security and efficiency, and thus realize the secure and traceable sharing of government data.