The invention relates to the field of nano material development and application, and discloses a method for synthesizing multi-
branch colloidal gold nano particles different in grain
diameter and high in light absorbing intensity through
colloidal gold seed mediation growth. The method comprises the steps that firstly, a conventional
trisodium citrate reduction method is adopted, Au3+ in
chloroauric acid molecules is reduced into Au0, and ball-shaped
colloidal gold seeds are obtained; then, the colloidal gold seeds are added into a growth solution, wherein the growth solution mainly comprises
ultrapure water,
chloroauric acid,
trisodium citrate and other solutions; a magnetic stirring device is used for performing slow stirring, after the solution is evenly mixed, the solution is heated to 50 DEG C, and the rotating speed is increased at the time; and meanwhile a sufficient
hydroquinone solution is added at a time, the temperature of the
mixed solution is maintained at 50 DEG C, heating is stopped after the reaction is continuously carried out for 10 min, and a multi-
branch colloidal gold solution high in light absorbing intensity can be obtained through cooling to the
room temperature. The method has the beneficial effects of being easy to operate, simple in procedure, rapid in reaction, good in
controllability, high in
repeatability and the like.