A ventilation and heat dissipation apparatus, wherein the ventilation and heat dissipation apparatus comprises: a main frame configured to be connected to a device to be ventilated and cooled, and a ventilation and heat dissipation assembly located inside the main frame, wherein the ventilation and heat dissipation assembly comprises a waterproof unit for preventing external water from entering the device to be ventilated and cooled, an external ventilation unit for allowing outside air to enter the main frame, and an internal ventilation unit for allowing heat generated during operation of the device to be ventilated and cooled to enter the main frame; the waterproof unit, including a waterproof board, is located between the external ventilation unit and the internal ventilation unit, and the external ventilation unit and the internal ventilation unit are arranged in a staggered manner, wherein the external ventilation unit and the internal ventilation unit are respectively located on two sides of the waterproof board and the position of the internal ventilation unit is not lower than the position of the external ventilation unit; and a bottom of the waterproof board is provided with a drainage hole, so that the external water on a side of the waterproof board that is located in the internal ventilation unit flows out through the drainage hole at the bottom of the waterproof board and is discharged through the external ventilation unit, wherein the main frame comprises a first side board, a second side board, a top board, a bottom board, and a side wall, wherein the first side board is connected to one side of the side wall, the second side board is connected to the other side of the side wall, one end of the side wall is connected to the top board, and the other end of the side wall is connected to the bottom board; and the side wall has a first opening adapted to the external ventilation unit and a second opening adapted to the internal ventilation unit, and wherein both the external ventilation unit and the main frame, and the internal ventilation unit and the main frame are detachably connected the ventilation and heat dissipation assembly comprises a waterproof unit for preventing external water from entering the device to be ventilated and cooled, an external ventilation unit for allowing outside air to enter the main frame, and an internal ventilation unit for allowing heat generated during operation of the device to be ventilated and cooled to enter the main frame; the waterproof unit, including a waterproof board, is located between the external ventilation unit and the internal ventilation unit, and the external ventilation unit and the internal ventilation unit are arranged in a staggered manner, wherein the external ventilation unit and the internal ventilation unit are respectively located on two sides of the waterproof board and the position of the internal ventilation unit is not lower than the position of the external ventilation unit; and a bottom of the waterproof board is provided with a drainage hole, so that the external water on a side of the waterproof board that is located in the internal ventilation unit flows out through the drainage hole at the bottom of the waterproof board and is discharged through the external ventilation unit, wherein the main frame comprises a first side board, a second side board, a top board, a bottom board, and a side wall, wherein the first side board is connected to one side of the side wall, the second side board is connected to the other side of the side wall, one end of the side wall is connected to the top board, and the other end of the side wall is connected to the bottom board; and the side wall has a first opening adapted to the external ventilation unit and a second opening adapted to the internal ventilation unit, and wherein both the external ventilation unit and the main frame, and the internal ventilation unit and the main frame are detachably connected