Impulsivity has been proposed as an important risk factor in Non-Suicidal Self-Injury (NSSI). Yet, research outcomes on the relationship of impulsivity to NSSI have been mixed. The present study clarifies this relationship using event-related potentials (ERPs), along with self-reports and behavioral measures. Study 1 aimed to detect the prediction of emotion dysregulation and impulsivity to NSSI. 820 local common high school students and 72 counterparts with problematic behaviors were surveyed, and then the relation among NSSI, difficulties of emotion regulation (DER) and impulsivity were investigated by self-report measurements. Regression analysis results indicated that both DER and impulsivity could well predict NSSI, and contribution of impulsivity was much bigger than that of DER. In Study 2, a Go/Nogo paradigm was adopted to test the impulsivity of the injurers using behavioural measures and Nogo-N2 of ERPs. Participants were 12 confirmed self-injurious adolescents and 12 typical school middle students chosen from Study 1. The group differences (injurers vs controls) in behavior (response time and false alarm) and ERPs index (N2 amplitude and latency in successful Nogo trials) were analyzed in detail. Results disclosed that the NSSI group’s probability of false alarm was higher than the control group’s probability of false alarm in both Go and Nogo trials. In ERPs experiment, the NSSI group’s N2 amplitudes were significantly higher than the controls in correct Nogo trials, and NSSI group’s N2 latencies were clearly more delayed than the controls’ in correct Nogo trial. Results from Nogo-N2 amplitudes and latencies combining with the topographic maps showed that impulse processes occurred in prefrontal cortex mainly. According to the results from self-reports, behavioural measures and Nogo-N2 of ERPs, it can be concluded that self-injurious adolescents possessed stronger impulsivity; and they needed much more neural energy to fulfill an impulse inhibition; moreover, they were insensitive to Nogo stimuli. The present study is the first to examin Nogo-N2 in NSSI, and provides further evidence for impaired response inhibition in NSSI.