A motor vehicle comprises an SCR aftertreatment system. The SCR aftertreatment system comprises a urea box and a urea jet device. The motor vehicle is characterized in that an injecting port of the urea box is formed in an engine bin. Various kinds of liquid such as engine cooling liquid, engine oil and a glass cleanser of light vehicles are stored in the engine bin, and liquid can be conveniently injected as long as an engine bin cover is opened. The urea box can be put in the engine bin or at other positions of a neighbor engine, and can also be arranged outside the engine bin. The urea jet device comprises a liquid pump driven by a solenoid device, and the liquid pump comprises a plunger pump or a diaphragm pump and can be arranged inside or outside the urea box. After the SCR aftertreatment system is adopted, expensive ternary catalysts do not need to be used and are replaced with low cost oxidized catalysts, and thus cost is reduced to a certain extent.