A smart device assembly and a protection case for a smart device are provided. The protection case includes a rear case and a cover plate. A membrane switch is placed in the cover plate, and an outer surface of the cover plate includes a key window arranged corresponding to a key portion in the membrane switch. An extension wire of a lower circuit layer of the membrane switch is extended out from the cover plate. A spring pogo pin connector is arranged on the extension wire of the lower circuit layer of the membrane switch. A slot is formed in the smart device. A pogo pin base connected to a GPIO pin of a processor of the smart device is disposed inside a body of the smart device. A contact point of the pogo pin base is exposed in the slot.