It is generally effective. The seal of the employer is not a necessary condition for the labor contract to take effect. In the absence of special agreement, the signatures of both parties to the labor contract can show that the labor contract is valid. Just because there is no official seal, it is legally untenable to assume that the labor contract has not taken effect. In order to prevent hidden dangers, when signing a labor contract, it is best to ask the employer to sign and affix the official seal. Although there are some flaws in the form of an unsealed contract, it cannot be considered invalid. As long as the contents of the contract are legal and there is no fraud or coercion between the two parties at the time of signing, the arbitration institution can completely regard it as a valid labor contract.