The invention relates to a universal method and system for realizing a sensing device for preventing passengers in a vehicle from being forgotten. The universal method and system for realizing the sensing device for preventing the passengers in the vehicle from being forgotten are designed to increase the identification accurate rate of preventing children from being forgotten in the vehicle. Theuniversal method and system for realizing the sensing device for preventing the passengers in the vehicle from being forgotten comprises the steps of judging whether a vehicle state event belongs to apreset alarming event or not; if so, judging whether the interior environment of the vehicle satisfies human body moving or not, whether a person makes a sound or not and/or whether the current vehicle interior environment data exceed a preset threshold value range or not; and if so, judging that one person is forgotten in the vehicle and transmitting alarming information; and otherwise, doing notreatment. The universal method and system for realizing the sensing device for preventing the passengers in the vehicle from being forgotten is applicable to all types and brands of vehicles withoutremodeling the vehicle; the universal method and system for realizing the sensing device for preventing the passengers in the vehicle from being forgotten can really be used once being plugged; and the cost is also greatly reduced.