This article theoretically analyzes the impact of external tariff policy uncertainty on residents' consumption and carries out empirical test by constructing county external tariff policy uncertainty indicators and a generalized difference-in-differences model. The theoretical analysis and empirical test find that the reduction of external tariff policy uncertainty expands county residents' consumption by increasing non-farm employment and per capita income. This conclusion still holds after the identification hypothesis test such as the parallel trend test, the expected effect test and a series of robustness tests. There are time-lagged and long-run effects of the impact of external tariff policy uncertainty on residents' consumption; and the analysis of heterogeneity finds that in the counties that are export-oriented, with manufacturing as the pillar industry and an active private economy, the consumption-boosting effect of reduced external tariff policy uncertainty is stronger. Policy implications include that China should use various ways to reduce external tariff policy uncertainty as well as encourage and support the development of private enterprises in order to stabilize employment, consumption and expectations.