This invention relates to an assemblage of a pilot valve, a electromagnet and a main relief valve. The pilot valve is a kind of direct-loading spring relief valve with an added electromagnetic controlling device, the disk of this valve is controlled by an electrical control system as well as the set pressure of the medium. The two control mechanisms may be compensatory to or independent of each other. The first throttle section is provided above the ring channel between the disk of the pilot valve and the guide seat, while the second throttle section, between the upper shoulder of the disk and the top of the guide seat. The back pressure difference needed for the disk to return to the closed position can be obtained by adjusting the pressure difference between the spaces be low and above the first throttle section.