A V-type 12-cylinder diesel engine, comprising: a V-shaped cylinder block provided with twelve cylinder holes arranged in a V shape in two rows, the angle between the two rows of the cylinder holes being 60 degrees, wherein twelve sleeves corresponding to the number of the cylinder holes are casted on the V-shaped cylinder block outside the two rows of cylinder holes, respectively; twelve single cylinder heads each mounted at corresponding cylinder port of the V-shaped cylinder block; an diesel supply system including a diesel tank, an diesel supply pipeline in fluid communication with the diesel tank, and twelve electric control unit pumps, wherein the twelve electric control unit pumps are mounted in the corresponding sleeve, respectively, each electric control unit pump being used for controlling diesel injection to each cylinder, and wherein the diesel supply pipeline comprises a left pipe and a right pipe that are connected with the twelve electric control unit pumps through a plurality of vertical high-pressure pipes; an air inlet system used for supplying fresh air to the V-type 12-cylinder diesel engine; a lubricating system comprising an oil pan, a pre-diesel supply pump, an oil pump, an oil filter and an oil cooler, wherein the oil pan is arranged at a bottom of the V-shaped cylinder block, the pre-diesel supply pump is arranged at a front side of the oil pan, the oil pump is arranged at a left lower position of a front end of the V-shaped cylinder block, and the oil filter and the oil cooler are both arranged at a left upper position of the front end of the V-shaped cylinder block; and a cooling system comprising a high temperature water circulation loop used for cooling the V-shaped cylinder block and the twelve single cylinder heads, and a low temperature water circulation loop used for cooling the oil cooler, wherein the low temperature water circulation loop comprises a rear row radiator and a low temperature water pump, and the high temperature water circulation loop comprises a front row radiator and a high temperature water pump. a V-shaped cylinder block provided with twelve cylinder holes arranged in a V shape in two rows, the angle between the two rows of the cylinder holes being 60 degrees, wherein twelve sleeves corresponding to the number of the cylinder holes are casted on the V-shaped cylinder block outside the two rows of cylinder holes, respectively; twelve single cylinder heads each mounted at corresponding cylinder port of the V-shaped cylinder block; an diesel supply system including a diesel tank, an diesel supply pipeline in fluid communication with the diesel tank, and twelve electric control unit pumps, wherein the twelve electric control unit pumps are mounted in the corresponding sleeve, respectively, each electric control unit pump being used for controlling diesel injection to each cylinder, and wherein the diesel supply pipeline comprises a left pipe and a right pipe that are connected with the twelve electric control unit pumps through a plurality of vertical high-pressure pipes; an air inlet system used for supplying fresh air to the V-type 12-cylinder diesel engine; a lubricating system comprising an oil pan, a pre-diesel supply pump, an oil pump, an oil filter and an oil cooler, wherein the oil pan is arranged at a bottom of the V-shaped cylinder block, the pre-diesel supply pump is arranged at a front side of the oil pan, the oil pump is arranged at a left lower position of a front end of the V-shaped cylinder block, and the oil filter and the oil cooler are both arranged at a left upper position of the front end of the V-shaped cylinder block; and a cooling system comprising a high temperature water circulation loop used for cooling the V-shaped cylinder block and the twelve single cylinder heads, and a low temperature water circulation loop used for cooling the oil cooler, wherein the low temperature water circulation loop comprises a rear row radiator and a low temperature water pump, and the high temperature water circulation loop comprises a front row radiator and a high temperature water pump.