It is acceptable to sign a contract with only one official seal. According to relevant legal provisions, a seal has the same legal effect as a signature. Therefore, if one party to the contract has an official seal but does not sign, it will not affect the establishment of the contract. Generally speaking, the presence of the official seal on the contract means that both parties have reached an agreement on the contents of the contract. According to Article 490 of the Civil Code, if the parties conclude a contract in the form of a contract, the contract is established when both parties sign, seal or fingerprint. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it. Laws and administrative regulations stipulate or the parties agree that a contract should be concluded in written form. If the parties do not use written form but one party has performed its main obligations and the other party accepts it, the contract is established. Article 490 of the Civil Code: If the parties conclude a contract in the form of a contract, the contract shall be established when both parties sign, seal or fingerprint the contract. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it. Laws and administrative regulations stipulate or the parties agree that a contract should be concluded in written form. If the parties do not use written form but one party has performed its main obligations and the other party accepts it, the contract is established.