Abstract: In order to remove fake coin real time and get rid of trouble of false coin, based on the measurement and research of characteristic parameter of usual one-yuan false coin, the paper sums up the differences of electrical characteristic parameter of real and false coin, presents a new rapid, lossless technique to discriminate false coin. Proposed method applies fixed frequency and partial resonance eddy-current sensor to measure voltage amplitude and has high discrimination ratio. Circuit design based on the new method is of low cost and high discrimination percentage, and it can be used in commercial field.