Abstract: So far in China, electro-magnetic valve and a micro computer for quantative control have been used in most of the oil distribution operation of product oil sales systems. Surge usually occurs in the piping system due to the short time it takes to close of electro-magnetic valve and the initia as well as compressibility of the liquid, which severely threatens safe operation. But problems can be solved if a relief valve is installed in parallel with the bypass of the electro-magnetic valve, so that, the liquid inside the piping can suddenly stop flowing if the electro-magnetic valve is stopped all of a sudden, the first layer liquid, with △s as its thickness, of the adjacent valve produces an increased surge pressure value——△p, which will get higher with △s getting thicker. If △s value decreases, it means △p value will decrease as well. The above mentioned pressure relief valve can help solve the problem. It works in this way: It closes when the compressed liquid pressure value reaches the set value and discharges part of the liquid thus avoiding surge occurance. This kind of relief valve is reliable in action, low in cost and free of maintenance, Another advantage is that it has wide scope of application for it has not power device therefore it is not interfered, while working, by any intelligent instrument. On top of what is mentioned above, the following are recommended: shut down the pump ahead of time, acquisite unit time flowrate, set pump shut-down time, decide when to close the valve to avoide surge.