The invention discloses a color sprayer special for watercolor paintings and a color spraying method. A pigment spraying head comprises an air pump; a switch of the air pump is connected with a pressing plate; a finger opening is formed in the bottom end of the pressing plate; the finger opening is matched with fingers; an internal thread connection opening is formed in the head end of an outer shell of the air pump; the internal thread connection opening is matched with all types of nozzles; the outer surface of the air pump is connected with an annular telescopic moving set piece; the annular telescopic moving set piece comprises a locating annular piece; the tail end of the locating annular piece is connected with a fixed annular shaft; the circular annular shaft is arranged at the head end of a cylinder I; a limiting bulge is arranged at the head end of the locating annular piece; the limiting bulge is matched with the tail part of a moving extending piece; an annular limiting frame is arranged at the tail part of the moving extending piece; the annular limiting frame is matched with the limiting bulge.