The invention discloses an efficient heat dissipation device for a power distribution cabinet for road lighting street lamps. The device includes a pedestal, a power distribution cabinet, a rainwatercollecting box and two sets of first box bodies; the power distribution cabinet is arranged on the top of the pedestal, and one side of the power distribution cabinet is a hollow structure; the rainwater collecting box is welded on the top of the power distribution cabinet; the two sides on the top of the pedestal are symmetrically welded with two sets of liquid storage tanks; the bottoms of the two sets of the liquid storage tanks pass through the pedestal; the bottom of one set of the liquid storage tank communicates with a water inlet pipe; and the other end of the water inlet pipe is welded with a water pump. Operators can move heat dissipation blocks in the power distribution cabinet by pulling a movable plate, so that the ventilation area of the power distribution cabinet can be enlarged, the ventilation effects of the power distribution cabinet can be improved, the heat dissipation rate of electronic components in the power distribution cabinet can be accelerated, and therefore,convenient usage can be achieved; and the rainwater collecting box can collect rainwater in snowy and rainy weather, so that the rainwater can cool U-shaped copper pipes, and therefore, resources canbe effectively utilized, and energy can be saved.