Abstract: An analytical method for the determination of sedaxane residues in brown rice was established by QuEChERS and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted with a mixture of acetonitrile and water (80/20, V/V), purified by dispersion solid phase extraction with PSA as sorbent, and quantified using LC-MS/MS by external standard method. The results showed that good linearity was obtained in the range from 0.001 to 0.1 mg/L, with R² > 0.996. At the fortified levels of 0.004, 0.01 and 0.1 mg/kg, the recoveries of sedaxane in brown rice samples were 83%-95% with the relative standard deviations (RSD) of 3.9%-12%. The limit of quantitation (LOQ) was 0.004 mg/kg in brown rice samples, which was significantly lower than the maximum residue limit (MRL) of 0.01 mg/kg set by the Codex Alimentarius Commission. The proposed method is simple, accurate and sensitive. Hence, it could be used for the detection of sedaxane residues in brown rice. A market survey of 40 brown rice samples from 6 provinces was carried out, and the residual amount of sedaxane was less than 0.004 mg/kg in all samples. The dietary risk assessment showed that the use of sedaxane in rice was currently at a low risk in China.