Legal analysis: if a contract is not signed or sealed, its validity should be determined according to the specific circumstances: the first is that only one party signs or seals, and one party (whether the signatory or the seal party) fulfills the main obligations of the contract and is accepted by the other party, then the contract is established, regardless of whether the recipient has fulfilled its due obligations; The second is that only one party signs or seals the contract. If one party (whether the signatory or the seal party) performs the main obligations of the contract, but it is not accepted by the other party, the contract is not established; The third is that only one party signs or seals the contract, but neither party has fulfilled the main obligations of the contract, and the contract is not established; The fourth is that both parties have not signed or sealed the contract, but one party has fulfilled its main obligations and is accepted by the other party, and the contract is established, regardless of whether the recipient has fulfilled its due obligations; The fifth is that the contract is not signed or sealed by both parties, and if one party has fulfilled its main obligations but has not been accepted by the other party, the contract is not established; The sixth is that neither party has signed or sealed the contract, and neither party has fulfilled the main obligations of the contract, so the contract is not established.

Legal basis: Article 502 of the General Principles of the Civil Law of People's Republic of China (PRC) * * * A contract established in accordance with the law shall come into effect upon its establishment, unless it is otherwise stipulated by law or agreed by the parties. In accordance with the provisions of laws and administrative regulations, if the contract should go through the approval procedures, such provisions shall prevail. If the failure to go through the formalities such as approval affects the effectiveness of the contract, it will not affect the performance of the obligation clauses such as approval and the effectiveness of relevant clauses in the contract. If the party that should go through the formalities for approval fails to perform its obligations, the other party may require it to bear the responsibility for violating its obligations. The modification, assignment and dissolution of a contract shall be subject to the provisions of laws and administrative regulations, and the provisions of the preceding paragraph shall apply and shall be subject to approval.

Article 503 A contract without agency shall be ratified by the principal. The agent has no right to conclude a contract in the name of the principal, and if the principal has started to perform the contractual obligations or accepted the performance of the counterpart, it shall be regarded as ratification of the contract.

Article 504 A contract concluded by the legal representative of a legal person or the person in charge of an unincorporated organization exceeds its authority, unless the other party knows or should know that it has exceeded its authority, the representative's behavior is valid, and the contract concluded is valid for the legal person or unincorporated organization.