Using big data web crawling techniques, this paper obtained specific information from self-built official websites of A-share listed companies between 2011 and 2021 to study the effects and mechanisms of internetization on enterprise labor investment efficiency. The paper finds that internetization significantly improves labor investment efficiency by reducing both over- and under-employment. After distinguishing between hiring and firing, we find that internetization decreases enterprises' over-hiring and over-firing. The conclusion remains robust after a series of robustness tests. Mechanism analysis indicates that internetiaztion improves enterprise labor investment efficiency by improving corporate information transparency, reducing the number of repetitive job positions and enhancing labor skills. Heterogeneity analysis shows that the enhancement effect of internetization on labor investment efficiency is more pronounced in highly competitive market environments. However, financial constraints inhibit the positive impact of internetiazion on labor investment efficiency. Finally, internetization improves labor investment efficiency, thereby reducing labor cost stickiness. This paper helps to reveal the relationship between internetization and human capital allocation efficiency at the micro level, and provides important insights for promoting internetization and optimal allocation of labor resources.