The utility model relates to a strut type structure for mounting of a lightning arrester on a +/-500V direct current power transmission line. The strut type structure comprises foundations, a tower leg, a variable-cross section tower body, an equal-cross section tower body, and a strut top end and lightning arrester body connecting plate, wherein the tower leg is fixedly arranged on the foundations, the variable-cross section tower body is arranged on the tower leg, the equal-cross section tower body is arranged on the variable-cross section tower body, and the strut top end and lightning arrester body connecting plate is arranged at the top end of the equal-cross section tower body. The strut type structure has the advantages that the tower leg is arranged on the foundations, the variable-cross section tower body is arranged on the tower leg, the equal-cross section tower body is arranged on the variable-cross section tower body, and the strut top end and lightning arrester body connecting plate is arranged on the equal-cross section tower body; the structure is independent from an iron tower of a running line, so the influence on the running line is avoided, and the modifying of the existing iron tower is not needed; the structure is simple, and the operation is easy; the method is a feasible, effective and easy method for mounting the lightning arrester on a strain tower or a line tower with difficulty in modifying the running line.