一、涉外合同的当事人选择解决合同争议所适用的法律,规避了我国的强制性或者禁止性法律规范的,其约定不发生法律效力。二、对外担保合同未按规定在行政管理机关办理批准登记手续的,依法应认定无效。对于造成合同无效,主债权人及担保人均有过错,应各自承担相应的责任。 First, the parties involved in a foreign contract choose to solve the law applicable to the contract dispute and evade the mandatory or prohibitive legal norms in our country, and the agreement does not have legal effect. Second, the external guarantee contract fails to go through the formalities for approval of registration in the administrative organ, shall be found invalid according to law. For the contract is invalid, the main creditors and guarantors have fault, each should bear the corresponding responsibility.