Abstract: Previous studies have explored the technological innovation behavior of enterprises from several perspectives, but the impact of customer concentration on enterprise innovation has not attracted enough attention of scholars. From the point of customer concentration, this paper discusses the influence of big customer relationship on enterprise technology innovation. Based on the analysis of China A-share manufacturing listed companies from 2009 to 2015, the study finds that customer concentration could hinder the innovation of enterprises. While the company's scale alleviates this negative impact, customer volatility aggravates the dilemma. Furthermore, this paper examines the inherent mechanism of the impact of customer concentration on enterprise innovation. As conclusions, firstly, the problems of going concern caused by customer concentration weaken the enterprise's risk-taking abilities. Secondly, through the passive increase of cash holdings and occupation of funds by significant customers, the enterprise's innovative resources are squeezed.