Tripyrasulfone is an 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide applied postemergence (POST) to control Echinochloa crus-galli (L.) P.Beauv. and other annual weeds in directly seeded and transplanted paddy fields in China. In this study, the baseline sensitivity to tripyrasulfone of E. crus-galli in paddy fields in China was established using dose-response assays between June and September 2020. The results showed that the sensitivity to tripyrasulfone varied among 58 populations collected from paddy fields in China. The tripyrasulfone dose causing a 50% growth reduction (GR₅₀) in the 58 field populations ranged from 1.95 to 46.47 g a.i. ha⁻¹, and no populations showed resistance to tripyrasulfone. At the same time, the GR₅₀ values were not normally distributed (P < 0.0001) but distributed as a unimodal curve, and the baseline sensitivity (GR₅₀b) to tripyrasulfone for E. crus-galli in paddy fields in China was 18.12 g a.i. ha⁻¹. The SI₅₀ value (the ratio between the GR₅₀ values of the least and most sensitive populations) showed 23.8-fold variability in tripyrasulfone sensitivity among the 58 E. crus-galli field populations, while the variability declined from 23.8-fold to 2.6-fold when the SI₅₀b value (the ratio between the GR₅₀ values of the least sensitive population and the GR₅₀b) was used. This study confirmed the effectiveness of tripyrasulfone against E. crus-galli in paddy fields in China and provided a reference for detecting time-dependent shifts in the tripyrasulfone sensitivity of E. crus-galli field populations.