Using the data of listed family enterprises in Shanghai and Shenzhen from 2008 to 2018 as research object, this paper empirically examines the influence of intergenerational succession mode of family businesses and family-based method on long-term investment decisions. The results show that, compared with the succession mode of professional managers, the investment scale of family businesses in the succession mode of sons inheriting from fathers declines greatly,but the main reduction lies in capital expenditure, and the proportion of R&D expenditure in long-term investment declines slightly. Moreover, compared with the indirectly established family enterprises, the directly established family enterprises are conducive to promoting the decline in the long-term investment scale of family enterprises, but inhibit the drop of R&D investment share in total investment under the mode of children inheritance.