Abstract: A 1 kW, 2.45 GHz multi-mode microwave reactor with continuous power supply was designed in order to conduct the non-catalytic transesterification for biodiesel production. The microwave source used in this reactor is magnetron and it is equipped with a temperature probe and pressure gauge for continuous monitoring purpose. Besides, the electric field and temperature distribution within the reactant medium (mixture of palm oil and dimethyl carbonate) under the microwave irradiation was investigated using a commercial finite element method (FEM) software, COMSOL Multiphysics 5.1. Maxwell’s equations and heat transport equation are coupled to describe the microwave heating process.