The invention relates to an idling start and stop system based on online algorithm optimization. The system comprises a central processing module (1), a power supply module (2), a data acquiring module (3), a communication module (4) and a driving module (5), and is characterized in that the central processing module (1) is responsible for acquiring signals of vehicle state parameters, exchanges data with the data acquiring module (3), the communication module (4) and the driving module (5) through a data bus, and analyzes switch signals and simulation signals of the vehicle state parameters based on an online algorithm to determine if a vehicle engine is located in a closing state or an opening state so as to send an instruction of controlling opening or closing of the engine to a ESM starter module and an electromagnetic valve driving circuit module. Before the idling start and stop system is operated, the idling start and stop are prejudged, so that the operation frequency of the system is reduced, and the control confusion of the idling start and stop system is reduced.