The invention provides a cylinder shutting down mode implementing method and system for an engine, and a vehicle. The method includes: selecting a plurality of engine rotation speeds, and performing load characteristic test in a plurality of preset cylinder shutting down modes at each engine rotation speed so as to acquire a plurality of groups of training samples; training a wavelet neural network according to the training samples; inputting running parameters of a vehicle into the trained wavelet neural network so as to determine the cylinder shutting down number and a cylinder shutting down sequence when it is determined that the vehicle enters a cylinder shutting down mode, generating a corresponding cylinder shutting down mode signal, and acquiring the air intake flow and the fuel injection amount of working cylinders according to the cylinder shutting down mode signal; and controlling a cylinder shutting down process of the engine according to the cylinder shutting down mode signal, and the air intake flow and the fuel injection amount of the working cylinders. The cylinder shutting down mode implementing method of the engine can ensure a cylinder shutting down effect (i.e., fuel economy, can improve the uniformity of the cylinders and the stability of working, can improve the reliability of the whole vehicle, and can improve the comfort of a driver.