【Abstract】”Labor contract law” stipulates that employers and workers should sign but do not sign a fixed term labor contract to bear the two times the legal liability. This kind of law has a great effect on the stability of labor relations in reality. However,there are differences between the upper limit of two times salary,the burden of proof and the understanding of the signing a non fixed term labor contract. The author puts forward his own opinion on the basis of law. 【關键词】无固定期限劳动合同;法律责任;二倍工资;上限;举证责任