To address the issues of insufficient concealment， long extraction time for hidden information， low hiding capacity， and single application scenarios in the existing blockchain covert communication schemes， a blockchain covert communication method based on Ethereum smart contracts and InterPlanetary File System （IPFS） technology was proposed. Firstly， IPFS was used to store long ciphertexts， and a combination of on-chain and off-chain storage was employed to compensate for the low efficiency and the high cost of blockchain storage. Secondly， by adopting the concepts of derivation relationships and codebooks， the separation of secret information and communication information was achieved， which meant that the on-chain data was index information of the ciphertext hash rather than the ciphertext hash itself， thereby further enhancing security. Thirdly， based on the index information， a suitable smart contract was customized， and the index information was disguised as normal contract call parameters to ensure both concealment and security. Moreover， the data field storage capacity for contract call transactions was relatively large， which could further enhance the information embedding of transactions. Finally， group encryption technology was introduced into the blockchain covert communication model to meet the multi-user interactive scenarios well. Experimental results show that the proposed method can further improve time efficiency and information embedding size， enhances concealment and security greatly， and can be applied to interaction scenarios with multiple receiving users.