Against the backdrop of escalating Sino-U.S. trade frictions, tariff shocks not only increase firms’ operating costs and external uncertainty but also exert profound impacts on their innovation strategy choices. This study investigates how firms select optimal innovation models under tariff shocks in order to effectively cope with external risks. Taking the temporary tariff increases imposed by the United States on China in 2018 as a quasi-natural experiment, this study uses A-share exporting firms listed on the Shanghai and Shenzhen Stock Exchanges during 2014-2023 as the research sample to systematically examine the effects of tariff shocks on firms’ innovation model choices. The results reveal that tariff shocks significantly suppress independent innovation activities through a “crowding-out effect.” Meanwhile, under the combined influence of the “crowding-out effect” and the “forcing effect,” tariff shocks exert a U-shaped impact on collaborative innovation-initially inhibiting and subsequently promoting it. In addition, moderation analysis uncovers the supply chain transmission mechanism of tariff shocks: tariff shocks borne by upstream suppliers strengthen the U-shaped relationship between firms’ own tariff shocks and collaborative innovation, while tariff shocks borne by downstream customers positively moderate the relationship between firms’ own tariff shocks and independent innovation. This study not only enriches the theoretical research on tariff shocks and corporate innovation strategies but also provides empirical evidence and practical insights for firms to optimize innovation strategies and strengthen organizational resilience in complex external environments.