Enhancing the total factor productivity of enterprises is crucial for achieving high-quality economic development in China. Taking the strategic alliance enterprises among A-share listed companies on the Shanghai and Shenzhen Stock Exchanges in China from 2014 to 2023 as the research sample, this study finds that when alliance enterprises shared auditors, it enhances learning ability, improves the information environment, strengthens supervision and counterbalance, and ultimately enhances the total factor productivity of enterprises, and external crisis situation intensifies the promoting effect of shared auditors on the total factor productivity of enterprises. After distinguishing the characteristics of both the supply and demand sides of auditing and the intermediary, it is found that when the alliance form is an equity alliance, the degree of cooperation is relatively high, the auditor is one of the “Big Four” firms, and the degree of analyst tracking is strong, the improvement effect is more obvious. The economic consequence test reveals that the positive effect of shared auditors on total factor productivity can improve enterprise performance. The research conclusion provides a possible explanation for the differentiated performance of competitive advantages of alliance enterprises, and has implications for promoting the high-quality development of enterprises.