<p>It is crucial to differentiate between quantitative job insecurity and qualitative job insecurity, as the concepts and impacts of these two types of job insecurity differ much. While some scholars are beginning to explore the positive effects of job insecurity, they often overlook and hence miss to address the coexistence of both positive and negative impacts. Drawing from the job demands-resources (JD-R) model and cognitive appraisal theory (CAT) of stress, we argued that there is a U-shaped relationship between quantitative job insecurity and organizational commitment, while there is a linear relationship between qualitative job insecurity and organizational commitment. This research employed a mixed method including empirical analysis (a two-wave study for 206 participants) and the qualitative interviews with 15 individuals. The obtained results verified the U-shaped effect of quantitative job insecurity and the linear effect of qualitative job insecurity. Further, psychological contract violation mediated the relationships between quantitative job insecurity, qualitative job insecurity and organizational commitment, while ICT demands have alleviated the effect of quantitative job insecurity on psychological contract violation. This research offered new theoretical and management insights to investigate the effects of quantitative and qualitative job insecurity.</p>