1. The car purchase contract with my signature is invalid. The criteria for signing a contract are as follows:

(1) If another person is authorized to sign the cooperation agreement within the agency authority, or if he knows that another person has signed the cooperation agreement in his own name and does not deny it, the signature is valid and the car purchase contract is valid;

(2) If the agent has no right to act as an agent, exceeds the agency's authority or is signed by others instead of himself after the agency's authority is terminated, the agency's signature is valid and the cooperation agreement is valid;

(3) A contract becomes effective as soon as it is formed, except as otherwise provided by law or agreed by the parties. If the party applying for approval fails to perform its obligations, the other party may require it to bear the liability for breach of contract.

2. Legal basis: Article 502 of the Civil Code of People's Republic of China (PRC).

A legally established contract shall come into force upon its establishment, except as 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.

Second, what should I pay attention to when signing a car purchase contract?

1, it is necessary to clearly specify the brand and car number of the car itself;

2. Pay attention to the details of the dealer's contractual responsibilities, including the delivery method and time;

3. In the car purchase contract, special attention should be paid to clarifying the liability for breach of contract, as well as the agreed settlement method and the jurisdiction of the contract;

4, indicate the after-sales service, should focus on what kind of obligations the dealer should bear;

The names on the bill must be the same.