[en] Liquid scintillation method is the most promising one to determine the radioactivity of pure beta-nuclides, especially low energy pure beta-emitters. Many works have been done in detail by it, but they are mainly limited to nuclides, high specific activity or standard solution available. A common method, for low specific activity or standard solution unavailable nuclides, is efficiency replacement. But it causes a large error. A simple and accuracy method was developed to solve the problem. Firstly, scaling the liquid scintillation spectrometer (Tricarb-3170) with 6 low energy beta-nuclides ("3H, "2"4"1Pu, "1"0"6Ru, "6"3Ni, "1"5"1Sm and "1"4C), whose energy varies evenly in the low energy region. Secondly, fitting a three-dimension surface by three variables, nuclide energy, quenching index and determining efficiency. Finally, a quenching-efficiency curve will be achieved for an interested nuclide since its energy is known quantity. In addition, five kinds of cocktails were compared and the effects of chemical quenching and color quenching on efficiency were studied. Uncertainty and detection limit of this method were done as well. (authors)