The utility model relates to a power transmission steel pipe tower and a cross arm connection joint thereof. The cross arm connection joint of the power transmission steel pipe tower is characterized in that principal materials of cross arms are connected with a principal material of a tower body through inserted plates, which are X-shaped or U-shaped inserted plates. A connection method provided by the utility model improves structural strength of the power transmission steel pipe tower and the cross arm connection joint thereof, thereby reducing consumption of steels and lowering requirement for the quality of the steels; and reduces welding quantity and difficulty greatly and lowers requirement for placing precision of workpieces, thereby shortening processing period.