A cooling system for an internal combustion engine, comprising a cooling fan , a first water radiator , an intercooler and a second water radiator , wherein the intercooler is positioned between the first water radiator and the second water radiator ; and the first water radiator , the intercooler and the second water radiator jointly form a heat exchange unit, and the cooling fan is provided on the outer side of the heat exchange unit; the first water radiator is provided with a first water inlet pipe (1-1), a first water inlet chamber (1-2), a first core body (1-3), a first water outlet chamber (1-4) and a first water outlet pipe (1-5) which are sequentially communicated; the second water radiator is provided with a second water inlet pipe (4-1), a second water inlet chamber (4-2), a second core body (4-3), a second water outlet chamber (4-4) and a second water outlet pipe (4-5) which are sequentially communicated; the first water outlet pipe (1-5) is communicated with the second water outlet pipe (4-5) by the first water outlet chamber (1-4) or a round pipe; the intercooler is provided with an air inlet pipe (2-1), an air inlet chamber (2-2), a third core body (2-3), an air outlet chamber (2-4) and an air outlet pipe (2-5) which are sequentially communicated; the cooling fan , the first water radiator and the intercooler are sequentially connected by cooling air blown by the cooling fan so as to form a serial type structure; the cooling fan , the intercooler and the second water radiator are sequentially connected by cooling air blown when the cooling fan works so as to form a serial type structure; and simultaneously, the first water radiator and the second water radiator are in a parallel type structure; characterized in that each of the first core body (1-3), the second core body (4-3) and the third core body (2-3) lies on a different parallel vertical surface relative to the cooling fan . the first water radiator is provided with a first water inlet pipe (1-1), a first water inlet chamber (1-2), a first core body (1-3), a first water outlet chamber (1-4) and a first water outlet pipe (1-5) which are sequentially communicated; the second water radiator is provided with a second water inlet pipe (4-1), a second water inlet chamber (4-2), a second core body (4-3), a second water outlet chamber (4-4) and a second water outlet pipe (4-5) which are sequentially communicated; the first water outlet pipe (1-5) is communicated with the second water outlet pipe (4-5) by the first water outlet chamber (1-4) or a round pipe; the intercooler is provided with an air inlet pipe (2-1), an air inlet chamber (2-2), a third core body (2-3), an air outlet chamber (2-4) and an air outlet pipe (2-5) which are sequentially communicated; the cooling fan , the first water radiator and the intercooler are sequentially connected by cooling air blown by the cooling fan so as to form a serial type structure; the cooling fan , the intercooler and the second water radiator are sequentially connected by cooling air blown when the cooling fan works so as to form a serial type structure; and simultaneously, the first water radiator and the second water radiator are in a parallel type structure; characterized in that each of the first core body (1-3), the second core body (4-3) and the third core body (2-3) lies on a different parallel vertical surface relative to the cooling fan . <EOS>