Abstract: Fire wall has the function of oil isolation and fire blocking. But it will affect fire fighting operation if it builds too high, furthermore, soil fire wall can't be kept integrate and will occupies larger area of land. If the fire wall can only stand with a static pressure from the oil contained, it will probably be damaged by the shock of the oil. The method using movable metal baffle and control valve near water sealed well to block the drain of oil tank group is unreliable and it will widen flowing fire area. The article gives an improving commendation and relative measure according to the problem of height, building material, strength and closure of the fire wall for oil tank group.