A photovoltaic junction box comprising a diode module and a circuit board disposed in a box body, and a heat sink mounted on the outer surface of the box body. The diode module is attached to the back side of the heat sink and is electrically connected to cooper conductor. The heat sink is made of aluminum material and a heat-absorbing layer is provided inside the heat sink. The heat-absorbing layer is close to the diode module. The aluminum heat sink provides great thermal conductivity, therefore, can greatly increase the cooling capacity of the junction box. In addition, because metal material for higher temperature resistance is used instead of lower temperature resistance plastic material, the box body would not deform as easy, greatly increase the safety and reliability of the junction box.