The invention provides a privacy preserving intelligent contract method in a block chain. The content information of a digital asset trading participant is encrypted in the intelligent contract, and ciphertext processing is carried out; the intelligent contract x adopts a Merkle tree structure, a leaf node of the Merkle tree is encrypted through a public key, and a Hash digest value is adopted to replace original data of a block head. In comparison with the prior art, in a block chain with data privacy preserving requirements, digital asset trading data and process privacy preserving functions are realized, the intelligent contract trading participant can only check the trading information, and the method can be applied to any block chain application scene with data privacy preserving requirements.