地下经济是处于国家正式统计和监管以外的各种经济活动的总称。文章应用通货需求法,利用1979～2009年的相关统计资料,测算了中国改革开放以来的地下经济规模,尝试探讨了地下经济的成因,并对地下经济的影响进行了实证分析。研究结果显示:中国地下经济规模占GDP总值,在1979～2009年介于0.78%～23.28%之间,较重的税收负担和政府管制是地下经济产生的主要原因。地下经济对官方经济具有一定的积极作用,而地下经济规模的扩大减少了财政收入,加剧了现阶段中国居民收入的不平等。 Underground economy is a general term for various economic activities outside the formal statistics and supervision of the state. This article uses the method of currency demand to analyze the underground economy scale of China since its reform and opening up and makes use of the relevant statistical data from 1979 to 2009 to explore the causes of the underground economy and make an empirical analysis of the impact of the underground economy. The result shows that the gross value of China’s underground economy accounts for between 0.78% and 23.28% between 1979 and 2009, and the heavy tax burden and government regulation are the main reasons for the underground economy. The underground economy has a positive effect on the official economy, while the expansion of the underground economy has reduced the fiscal revenue and exacerbated the inequality in the incomes of Chinese residents at this stage.