Tax incentives for human capital accumulation and enterprise innovation quality: Evidence of a quasi-natural experiment in China

•Tax incentives for human capital accumulation can improve the quality of enterprise innovation significantly.•Tax incentives for human capital accumulation can also enhance a firm's human capital accumulation and alleviate financial constraints.•This policy has a stronger positive effect in eras with denser human capital and higher finance development levels. This study analyzes the impact of human capital tax incentives on enterprise innovation quality. For this purpose, it designs as a quasi-natural experiment, using China's pre-tax deduction policy for employee education and training expenses. The results confirm that tax incentives for human capital accumulation significantly enhance corporate innovation quality. The primary mechanisms driving this effect are the alleviation of financial constraints and the promotion of human capital accumulation. Moreover, this effect is stronger in regions with higher levels of financial development and greater human capital density.