Fluazaindolizine suspension concentrate (500 g L-1 SC), as a pre-commercialized product, was firstly investigated under open-field conditions. A sensitive method for simultaneous determination of fluazaindolizine and seven metabolites (IN-QEK31, IN-F4106, IN-A5760, IN-UJV12, IN-UNS90, IN-QZY47 and IN-TMQ01) was established and validated using HPLC-QqQ-MS/MS technique. The LOQs of these pollutants in tomato were 0.01 mgkg(-1), and their recoveries were 81.1%-117% with the relative standard deviations (RSDs < 11.8%). The dissipation behaviours of fluazaindolizine in soil followed first-order kinetics with the half lives of 4.6-32.4 days, whilst the residues in plant were below its LOQ after 7 days. The fluazaindolizine residues in soil were below 0.963 mgkg(-1), based on root irrigation applications (50-75 mg a.i. per plant) twice and pre-harvest interval (PHI, 3 days), while the residues of IN-QEK31, IN-F4106 and IN-A5760 were below 3.9 mg kg(-1), excluding other four metabolites ( < 0.01 mgkg(-1)). The residues of fluazaindolizine in tomato were below 0.01 mgkg(-1), and IN-QEK31 remained 0.135 mg kg(-1). The current study could not only guide reasonable usage of the formulation, but also facilitate the setting of residue definition and its maximum residue limits (MRLs) of fluazaindolizine in tomato. (C) 2017 Elsevier B.V. All rights reserved.