A modified QuEChERS method combined liquid chromatography-tandem triple quadrupole mass spectrometry (HPLC-MS/MS) was developed for three novel pesticides, albendazole, flusilazole and imazalil, which are used for the control of tobacco leaf spot diseases. The established analytical method was applied for the study of dynamics and residue characteristics of the three fungicides under field conditions, the results of which could provide references for the establishment of related maximum residue limits (MRLs). The recoveries of albendazole, flusilazole, and imazalil in tobacco leaves were 84.9 %-104.4 %, 75.8 %-103.0 %, and 83.7 %-92.5 %, respectively, with relative standard deviations (RSDs) 1.2 %-8.1 %, 1.0 %-7.8 %, 2.8 %-8.8 %. The sensitivity, accuracy and reproducibility met the method requirements for pesticide residue analysis. The half-lives of albendazole, flusilazole, and imazalil in fresh tobacco leaves were 5.4-16.1, 4.3-7.7, and 4.4-6.9 days. When the fungicide was applied three times at the recommended maximum dose and 1.5-fold dose, the terminal residues of albendazole, flusilazole, and imazalil in cured tobacco leaves were 0.33-1.33 mg/kg, 0.17-1.00 mg/kg, and 0.76-2.00 mg/kg with a pre-harvest interval (PHI) of 14 days. Based on these test results, possible MRLs in tobacco for albendazole, flusilazole, and imazalil, derived on the same principles used for setting MRLs for food and feed, are 2 mg/kg, 2 mg/kg, and 5 mg/kg, respectively.