The invention discloses an oil tank level transmitting device comprising a sensing part and a signal transmitting part which are electrically connected in a sleeve tube, wherein the sleeve tube is a sealing sleeve tube formed by an upper cover (1) and a base (8); the end part of the base (8) is provided with a window (9) on which the sensing part is arranged; the sensing part is a capacitance type pressure sensing part (6) formed by a capacity voltage converter (61), and a tabulate capacitance upper polar plate (62) and a tabulate capacitance lower polar plate (63); the output end of the capacity voltage converter (61) is electrically connected with the signal transmitting part through a sealing adapter plate (4); the sealing adapter plate (4) is positioned between the capacitance type pressure sensing part (6) and the signal transmitting part, and is provided with electric welding points penetrating through the plate body of the sealing adapter plate (4) and a waterproof molecule plug; and the signal transmitting part is a cable (2) axially and hermetically sheathed with a conducting wire and an air duct. The invention can be used for accurately measuring the oil level in the non-pressure oil tank and can be widely applied to oilfield production.