Abstract: An oil-electricity separation type diesel heater comprises an outer shell (2), heating bars (1) and a temperature controller (3). Each of the heating bars (1) includes an electrode piece, a heating piece and an outer covering shell, and is connected to the wiring end of the temperature controller (3) by the electrode piece, and fixedly connected to the outer shell (2) by one end. The temperature controller (3) is arranged inside the outer shell (2), the gaps of the outer shell (2) are filled with a pouring sealant, and a hole (5) is arranged on the outer shell (2) to fix the heater at a mounting position. The heater produced by heating elements can rapidly and evenly be conducted to the diesel so as to reduce the viscosity of the diesel and improve its fluidity, and then optimize the combustion process of the diesel oil. The heater is low-cost, compact in structure, safe and reliable, and convenient for maintenance.