The invention relates to the technical field of tank trucks, in particular to a tank roof fence device of a tank truck. The tank roof fence device of the tank truck comprises a fence, wherein the fence is arranged on the tank roof; the fence comprises a front enclosing plate, a back enclosing plate and side enclosing plates which are respectively arranged at both side ends of the front enclosing plate and the back enclosing plate; the bottom of the front enclosing plate and the bottom of the back enclosing plate are welded on the tank roof; the bottoms of the side enclosing plates are bonded to the tank roof; the inner sides of the side enclosing plates are respectively provided with fence support seats and tank body lifting lugs; the bottoms of the fence support seats and the bottoms of the tank body lifting lugs are welded on the tank roof; the tops of the side enclosing plates are provided with buffer rods, and the buffer rods are of sealed or half sealed hollow structures; and the fence device also comprises a guardrail mechanism, and the guardrail mechanism is arranged at one side of the side enclosing plates at least. Compared with the prior art, the tank roof fence device disclosed by the invention has the advantages of high safety performance, light weight, low energy consumption, simple process and cost saving.