This paper presents a method on improving Cerenkov radiation counting efficiency for

32

P

132

I

45

Ca

35

S and

14

C radionuclides by using the emulsifier and wavelength shifter mixed solution as medium. The use of this mixed-medium for Cerenkov counting of high-energy β emitters is able to increase the counting efficiency 40% to 50% as compared

to

the water medium

and even the low-energy β emitters which below the Cerenkov threshold can also obtain higher counting efficiency. It is found that this method shows good stability

strong resistance to chemical quencher. In addition

it is particularly advantageous to large volume of aqueous sample and more convenient for sample preparation. The action mechanism of both the emulsifier and the wavelength shifter in the mixed-medium has also been discussed.