The invention relates to a novel oil tank isolating valve. The novel oil tank isolating valve comprises a valve body. The valve body is provided with a first pipe, a second pipe and a containing cavity, wherein the containing cavity communicates with the first pipe and the second pipe. A valve element is arranged in the containing cavity in a matched manner. The top of the valve element is connected with a solenoid valve, and a spring A is arranged in the middle of the valve element in a sleeving manner, wherein the spring A is located inside the containing cavity. The valve element is internally provided with a long groove, a first hole and a second hole. A core column is arranged in the long groove in a matched manner. A spring B is connected to the top of the core column. The core column is internally provided with a ventilating hole channel. The valve element is connected with a locating mechanism. The second pipe is internally provided with a partition plate and divided into two equal pipe bodies through the partition plate. By means of the novel oil tank isolating valve, the complex working conditions such as high-pressure exhaust, negative-pressure air supplementation and refueling exhaust can be achieved; the novel oil tank isolating valve can meet exhaust requirements under different pressure conditions and has the advantages of being more thorough and faster in exhaust and higher in efficiency; and the whole isolating valve is compact in structure, small in size, great in function and easy to operate, and the mounting space is greatly saved.