PurposeInnovation is the most important quality of enterprise management. It is an important and controversial issue whether the heterosexual leadership structure of the chairman and chief executive officer (CEO) makes the work “easy” or “very tired” in enterprise innovation. This study investigates the specific impact of the heterosexual leadership structure on enterprise innovation investment, and further explores influence mechanism between them from two perspectives. Specifically, from the perspective of enterprise leaders including the chairman and CEO, this paper analyzes the impact of surname sharing, intergenerational differences and top management team (TMT) external social network between the heterosexual leadership structure and enterprise innovation investment. And from the perspective of enterprise itself, this study explores the impact of ownership and organizational slack between the heterosexual leadership structure and enterprise innovation investment.Design/methodology/approachBy using ordinary least squares regression (OLS), this study mainly takes the unbalanced panel data of A-share listed companies from 2008 to 2019 in Shanghai and Shenzhen as the research sample to empirically analyze the relationship and influence mechanism between the heterosexual leadership structure and enterprise innovation investment.FindingsThe results show that the heterosexual leadership structure of the chairman and CEO has a negative impact on enterprise innovation investment. Surname sharing and ownership positively moderate the negative impact of the heterosexual leadership structure of the chairman and CEO on enterprise innovation investment. Intergenerational differences and TMT external social network negatively moderate the relationship between the heterosexual leadership structure of the chairman and CEO and enterprise innovation investment. In addition, the moderating effects of intergenerational differences and TMT external social network on the relationship between the heterosexual leadership structure and enterprise innovation investment both depend on organizational slack. When organizational slack is lower and intergenerational differences are higher, the negative impact of the heterosexual leadership structure of the chairman and CEO on enterprise innovation investment will be the strongest. And when organizational slack is lower and TMT external social network is higher, the negative impact of the heterosexual leadership structure of the chairman and CEO on enterprise innovation investment will be the strongest.Originality/valueBy exploring the influence and the boundary mechanism of the heterosexual leadership structure of the chairman and CEO on enterprise innovation investment, the “heterosexual difference effect” is verified in this paper, that is, when men and women work together, work is very tired. This not only enriches the existing research of enterprise innovation investment, but also provides practical guidance for effectively improving enterprise innovation investment from a new perspective. In addition, it broadens the moderating mechanism of the impact of the heterosexual leadership structure of the chairman and CEO on enterprise innovation investment, which is conducive to reasonable response to improve enterprise innovation investment.