The utility model provides an oil mist collecting device, including the outer circulative cooling ware of fluid, there is the cooling tube in the upper end UNICOM of the outer circulative cooling ware of fluid, cooling tube other end UNICOM has the fluid that sets up circulative cooling ware side outside fluid to store the box, be equipped with discharge valve on the cooling tube, the utility model discloses simple structure, behind outer this the oil collection fog device of circulative cooling ware top installation of fluid, inspection cooler top is polluted by the oil mist no longer, and field device is clean, also can reduce the waste of fluid, and the device preparation is simple and convenient, easy dismounting, collecting effect is good.