Abstract: In order to solve the limitations of large-scale testing instruments for the convenient and fast detection of simetryn, the molecular imprinting electrochemical sensor of simetryn (SMT) was prepared by in-situ initiation polymerization. The film was directly thermally polymerized on the surface of glassy carbon electrodes with simetryn as template molecule and methacrylic acid was used as the functional monomer. The sensor was then applied to detect the content of simetryn in samples. The electrochemical performance of the electrochemical sensor was tested by cyclic voltammetry (CV). The test results were verified by the ultra high performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The results show that the electrochemical sensor prepared by thermal polymerization at a dosage of 10 μL pre-polymerization liquid and a coating temperature of 60 ℃ has good selectivity, repeatability and stability. The detection linear relationship were I₁=−3.33c+39.03 (0.5-1 μmol/L) and I₂=−0.75c+35.52 (2-30 μmol/L) respectively. The correlation coefficients were r₁ = 0.985 and r₂ = 0.997. And the detection limits (LOD) were LOD₁ = 0.13 μmol/L and LOD₂ = 0.89 μmol/L. When the molecular imprinting electrochemical method was applied to determine the content of simetryn in tobacco leaves, the imprinted electrode could complete the adsorption of simetryn in the ertact solution of spiked tobacco leaves in 8 min, with a recovery rate of 76%-88%. The relative standard deviation was 2.7%-7.6%. This method can preliminarily meet the needs of rapid detection of simetryn in tobacco.