We generated and observed GHz ultrasonic waves on liquid surfaces for the first time using the transient reflecting grating (TRG) method. Three samples were used for measurement: two types of black inks and an aqueous solution of crystal violet (CV). We have investigated the pump power and the solute concentration dependencies of the intensities of the TRG signals from surfaces of the samples. As a result, it was found that these dependencies of the TRG signals are intrinsic to solute and dispersoid. These results presumably suggest that the TRG signals from the liquid surfaces reflect the dynamics of the energy transfer between solute and solvent molecules and of the adsorption and desorption on the liquid surfaces.