Legal analysis: The validity of the contract mainly lies in the Labor Contract Law of People's Republic of China (PRC) and the Civil Code of People's Republic of China (PRC), including: 1. The valid elements of a contract do not violate the interests of the law and society, and the intention is true. The parties have the corresponding ability to conclude a contract and conform to the legal form. 2. One party to an invalid contract uses fraudulent means, malicious collusion and legal means to cover up illegal purposes, which harms the interests of the public and violates the law. So the contract signed with the intermediary is valid.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 493 Where a contract is concluded by the parties in the form of a contract, the place where the contract is finally signed, sealed or fingerprinted is the place where the contract is established, unless otherwise agreed by the parties.

Article 502 A lawfully formed contract shall become effective upon its formation, unless otherwise provided 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.