In order to meet the requirements of pasteurization and sterilization， the conduction heating of liquid food with steam as the heat source usually exist serious heat loss and fouling of the pipeline， which can be solved by microwaves with its dielectric heating properties. In this study， the numerical analysis of the electric field distribution in a novel continuous-flow microwave heating equipment was performed by a coupled multi-physics simulation model， and the effects of operating parameters such as volume flow， input power and microwave frequency on the thermal response were investigated. The accuracy and validity of the simulation model was confirmed by comparing the average outlet temperature in both calculated and experimental results. The results show that the heat absorption of fluid is closely related to the electric field distribution in the resonant cavity， which directly determines the temperature distribution during the heating process， and the region with high field strength is conducive to increasing the fluid heating rate. In addition， the rapid heating region can improve the heating effect of other areas inside the pipeline by means of fluid heat transfer. The changes in volume flow and input power indirectly affect the contribution of dielectric heating and fluid heat transfer to the thermal response， and the microwave frequency also can directly affect the heating effect. The simulation model can comprehensively consider the multiple factors and predict the heating effect， which is helpful to analyze the electromagnetic thermal response of the fluid and promote the microwave replacement of the liquid food thermal processing.