Flumorph is a new fungicide, thermal hazard study and kinetic analysis for the process will solve engineering problems and ensure production safety. The thermostability of main materials is tested by using differential scanning calorimetry-thermogravimetric analyzer (DSC-TG). The reaction thermal behavior is studied by using reaction calorimeter (RC1), and the kinetic study of the reaction is carried out in this paper. The conclusion of this study is that the endothermic decomposition temperature of main intermediate of (3,4-dimethoxyphenyl)(4-fluorophenyl)methanone is 559.3 K. The exothermic decomposition temperature of N-acetylmorpholine is 478.2 K and the endothermic decomposition temperature of flumorph is 638.6 K. The exothermic energy of the reaction for synthesis of flumorph is 15.44 kJ/mol, and the adiabatic temperature rise is 9.1 K. This process is with lower thermal hazard. The reaction kinetic equation is r_A=kc_A^a=8.34×10^-3C_A^0.57, and the reaction order is 0.57 for (3,4-dimethoxyphenyl)(4-fluorophenyl)- methanone.