Abstract: The invention provides a three-way catalytic converter preheating control method and system, a vehicle and a storage medium. The includes when the temperature of an exhaust pipe of the hybrid electric vehicle is lower than a first temperature threshold value, sending a first work instruction; the high-low pressure conversion module outputting a first working voltage according to the first working instruction so as to start preheating of a catalyst in a three-way catalytic converter; when working data of the hybrid electric vehicle meets the switching condition, sending a second working instruction to make the high-low voltage conversion module outputs a second working voltage and stops outputting the first working voltage so as to stop the electric heating. According to the invention, two working modes can be provided, and the power battery can be used for electrically heating the catalyst in advance through the high-low pressure conversion module.