我国的不当得利理论研究已经初步形成规模,但在司法实践中的不当得利纠纷中,仍然存在很多争议的问题,尤其是对于诉讼中“无合法依据”这一举证责任的分配,更为突出。本文将从分析我国关于该构成要件的界定以及其举证责任现状,采其其合理内核,参考域内外关于该举证责任的规定以期提出自己的完善意见。 However, there are still many controversial issues in the unjust enrichment dispute in judicial practice, especially for the distribution of the burden of proof in the lawsuits, such as “no legal basis” More prominent. Based on the analysis of the definition of China’s constituent elements and the status quo of its burden of proof, this article adopts its reasonable core to refer to the provisions concerning the burden of proof both inside and outside the country with a view to presenting its own opinions.