With the layout space condition of AC diesel locomotives getting worse, the split cooling mode for large components& motors and traditional cooling tower structure have shown great limitations. Therefore, a new cooling mode was proposed, which combined the cooling system of air-cooled components(traction motor or main generator) and water-cooled components(converter modules in converter cabinet) organically, making full use of the cooling temperature differences of each cooling link to perform effective cooling for heating equipment. This integrated arrangement fully reduced the layout space of the ventilation and cooling devices of the two major components of locomotives, effectively optimized the overall layout, reduced the auxiliary power of locomotives, and improved the efficiency of locomotives.