Legal analysis: Only the labor contract signed by employees has no legal effect. According to the law, a contract is a written expression of the agreed contents reached by both parties, and it has legal effect only after being signed by both parties. If only one party signs and the other party doesn't, it can't be said that both parties have reached an agreement, and the contract is not established, of course, it has no legal effect. However, after the unit signs or seals, the contract is established and has legal effect.

Legal basis: People's Republic of China (PRC) Labor Contract Law.

Article 3 The conclusion of a labor contract shall follow the principles of legality, fairness, equality, voluntariness, consensus through consultation, honesty and credibility. The labor contract concluded according to law is binding, and the employer and the employee shall perform the obligations stipulated in the labor contract.

Article 10 To establish labor relations, a written labor contract shall be concluded. If a labor relationship has been established and a written labor contract has not been concluded at the same time, a written labor contract shall be concluded within one month from the date of employment. If the employer and the employee conclude a labor contract before employment, the labor relationship shall be established from the date of employment.

Article 36 The employing unit and the employee may terminate the labor contract through consultation.