An air-flow channel structure of an air pump, a micro air pump, a waterproof air pump, and an inflatable product are provided. The air-flow channel structure of the air pump includes an air chamber. The air inlet of the air chamber communicates with an axial-direction air inlet of the centrifugal impeller arranged inside the air chamber. The air chamber is formed with an air-guiding wall inside that gradually expands in a spiral shape around an axis of the centrifugal impeller. An air-guiding channel is formed between the air-guiding wall and the centrifugal impeller. A tangent air outlet is provided at the tail end of the air-guiding channel. The micro air pump is configured with the air-flow channel structure of air pump. The waterproof air pump includes a waterproof exterior shell and the micro air pump removably connected to the waterproof exterior shell inside.