A multiple detection system is applied to a vehicle and includes a contact-type detection module adapted to generate a contact-type detection datum, a contactless-type detection module adapted to generate a contactless-type detection datum, and an operation processor electrically connected with the contact-type detection module and the contactless-type detection module in a wire manner or in a wireless manner. The operation processor sets at least one of the contact-type detection datum and the contactless-type detection datum according to an environmental status of the vehicle to be a main detection result of the multiple detection system, and further sets the other detection datum to be an auxiliary detection result of the multiple detection system, for acquiring a passenger feature inside the vehicle.