With the rapid development of the Internet and big data technology, ecological big data, as the key foundation of ecosystem scientific research, has become the core support for solving ecological environment problems at present. Therefore, the safe sharing of ecological big data is crucial. Aiming at the problems of “data silo” and easy to be tampered with in the secure sharing of ecological big data, this study proposes a blockchain-based ecological big data secure storage and sharing scheme, which combines the blockchain and the interplanetary file system (IPFS) to carry out distributed storage and constructs a distributed, tamper-resistant system architecture, realizing the secure storage and sharing of ecological big data; for the secure storage and sharing of ecological big data, it is necessary to use blockchain as the key foundation for scientific research on ecosystems, which is the core support for solving ecological problems. For the problem that private ecological data is easily leaked, this study proposes an access control policy and designs a hierarchical ciphertext attribute-based (CP-ABE) encryption algorithm, which divides the attributes of ecological big data according to different sensitivities, and encrypts data with different sensitivities using the designed hierarchical CP-ABE encryption algorithm in order to prevent the leakage of the data. Finally, the smart contract is used to check the data visitors for misbehavior and realize fine-grained access control. The security analysis shows that this architecture can effectively realize the secure storage and sharing of ecological big data. The performance analysis shows that the hierarchical CP-ABE encryption algorithm enhances the protection of high privacy data.