The utility model relates to an engine oil pressure sensor assembly, belongs to the technical field of engine oil pressure monitoring and mainly solves the problems that the engine oil pressure sensor is high in cost and poor in tightness and a diaphragm deforms during production. The engine oil pressure sensor assembly is mainly characterized by comprising a housing assembly, a lower spring holder, a measuring spring and an end knob assembly; the housing assembly is composed of a housing, a seal gasket, a diaphragm, a pressure plate and an ejector core; the seal gasket, the diaphragm, the pressure plate and the ejector core are fixed in a cavity of the housing by riveting; one side of the ejector core is in contact with the diaphragm, and the other side of the ejector core penetrates a through hole of the pressure plate; the end knob assembly is composed of an insert and an end knob housing; the lower spring holder is mounted on the ejector core through a central through hole; the measuring spring is disposed between the lower spring holder and the insert. The engine oil pressure sensor assembly mainly applied to automatic monitoring of automotive engine oil pressure sensors has the advantages of compact structure, light weight, no defects such as oil seepage or leakage, long service life, and high operational reliability.