Based on resource dependence theory, this study examines the impact of customer concentration on innovation resources and innovation behaviors from the customer perspective. Specifically, it explores the non-linear effects of customer concentration on firm’s innovation performance and the contextual role of organizational slack resources. Selecting the Chinese listed information technology firms from the period 2007 to 2016 as empirical research samples, this study found that (1) customer concentration has an inverted U-shaped relationship with innovation performance; (2) both negative and positive effects will be weakened with the increase of absorbed slack.