An exhaust purification device for vehicles comprises a connection unit, a combustion unit, a buffer unit, a filtration unit, an emission unit, and a control unit. The connection unit is adapted to be connected to an exhaust pipe of a vehicle's engine. The combustion unit includes a main housing, a fuel-atomization nozzle, and an igniter. The nozzle and the igniter are arranged in an open-end container. The nozzle is connected to a fuel tank. An air pump is connected to the open-end container. The buffer unit is provided with a temperature sensor, an exhaust-buffering mask, and a fan. The filtration unit can remove the soot contained in the exhaust gas. The emission unit includes an L-shaped porous tail pipe being sealed with a porous cover. The control unit is electrically connected with the igniter, the fuel pump, the air pump, and the temperature sensor for controlling their operations.