The reasons why this contract is invalid are as follows:

1. A contract signed by a person without civil capacity is invalid;

2, the actor and the relative person with false meaning that the contract is invalid;

3. A contract that violates the mandatory provisions of laws and administrative regulations is invalid;

4. A contract that violates public order and good customs is invalid;

5, malicious collusion, damage the legitimate rights and interests of others contract is invalid.

Before the contract comes into effect, it is generally impossible to claim the liability for breach of contract, but only the liability for negligence in contracting. In the process of concluding a contract, the parties shall be liable for compensation under any of the following circumstances:

1, conclude a contract under the guise of malicious consultation;

2. Deliberately concealing important facts related to the conclusion of a contract or providing false information;

3. There are other acts that violate the principle of good faith.

The conditions for the contract to take effect are:

1, the parties have the corresponding ability to conclude a contract. A contract is an act that the parties consciously pursue specific legal consequences for the purpose of establishing, changing and terminating civil rights and obligations, which is directly related to the interests and losses of the parties. Therefore, the parties must be able to recognize and identify their actions and judge the legal consequences of their actions, that is, they must have the corresponding ability to conclude contracts;

2. Meaning is truth. The truthfulness of the expression of will is an important part of the validity of the contract, which means that the expression of ideology should truly reflect its inner meaning. A contract is a product of unanimity of will and an agreement between the parties. Whether this agreement has legal effect depends on whether the expression of will is true;

3. It does not violate the legal and social interests. Legitimacy is the essential attribute of civil juristic act, and it is also a necessary condition for the validity of civil juristic act. The legal effect of a contract lies in the fact that the parties' expression of will conforms to the law. Obviously, an illegal contract cannot be protected by law, nor can it produce the legal effect expected by the parties. At the same time, the contract should not only comply with the law, but also not violate the public interest in content;

4. The form is legal. The parties may conclude a contract in writing, orally or in other forms.

To sum up, the contract with forged signature is invalid.

Legal basis:

Article 143 of the Civil Code of People's Republic of China (PRC)

A civil juristic act that meets the following conditions is valid:

(1) The actor has corresponding capacity for civil conduct;

(2) the meaning is true;

(three) does not violate the mandatory provisions of laws and administrative regulations, and does not violate public order and good customs.