The present invention discloses the method for forming the coating having the composite coating particle size and the coating formed thereby, comprising the steps of: receiving, from a powder supply portion, a plurality of powders within a first powder particle size range, and transporting the powders using a transport gas; and forming a coating in which a plurality of first particles within a first coating particle size range and a plurality of second particles within a second coating particle size range, which is larger than the first coating particle size range, by causing the transported powders to collide with a substrate inside a process chamber at the speed of 100 to 500 m/s so as to be pulverized.