Legal analysis: If both parties agree, traditional Chinese characters can be used in the contract. Whether an alteration on a contract is valid or not depends on the following situations: 1. After the contract is signed, if either party uses illegal means to control others, steal the contract, modify or forge the contract for its own benefit, the modified part of the contract will be invalid and the original contract content will remain unchanged. ; 2. After the contract is signed, if either party wants to modify the contract, it must inform the other party. After both parties reach consensus, the contract can be re-signed or the corresponding clauses of the original contract should be modified or supplemented, and the official seals or personal fingerprints of both parties should be stamped on the modified places. . If there is only a verbal agreement but no modifications to the contract or no seal or fingerprint on any modification or change, it will be deemed invalid and the contract will continue to be effective as it is.

Legal basis: Article 143 of the "People's Republic of China and Civil Code" is valid if the following conditions are met:

(1) The actor has the appropriate qualifications capacity for civil conduct;

(2) The expression of intention is true;

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