Abstract: As a way of administrative activities, administrative contracts need to comply with the principle of administration by congress's laws; as having the attributes of contracts, administrative contracts must abide by the basic principles of contracts. The nullity standard of administrative act may be applied in the declaration of the nullity of administrative contract, but there may still be special nullity standards for the administrative contract; the nullity standard of the civil contract law may also apply mutatis mutandis, but it still needs to be coordinated with the principle of public law. The determination and selection of the nullity standard of administrative contact requires the measurement of values between the principle of administration by congress's laws, strict adherence to the law, the superiority of law, the stability of law and reliance protection.