Based on the efficiency-equity framework under the guidance of common prosperity, this study selects six key factors—level of economic development, industrial structure, financial development, education level, medical conditions, and fiscal expenditure, and employs a mixed-method approach combining fsQCA and regression analysis. Taking 982 counties in China as the research sample, it investigates the multiple concurrent causal paths of county entrepreneurial activity and their impact on employment levels. The findings reveal that: none of the six key factors alone constitutes a necessary condition for high county-level entrepreneurial activity; Four configurational paths lead to high entrepreneurial activity, namely the market-driven industry-education integration configuration(H1),the finance-driven talent empowerment configuration(H2),the industry-finance synergy with health security configuration(H3),and the factor synergy for common prosperity configuration(H4);These four configurations differ in their effects on the synergistic development of entrepreneurship and employment.H1 promotes county-level entrepreneurship but inhibits employment, whereas H2,H3,and H4 can achieve the synergistic development of entrepreneurship and employment.