Method for measuring dielectric constant of multilayer printed circuit board and system thereof

The invention provides a method for measuring the dielectric constant of a multilayer printed circuit board. The multilayer printed circuit board comprises a first external surface and a second external surface which are opposite and at least one intermediate layer which is arranged between the first external surface and the second external surface. The method comprises the steps that a signal is inputted from the first external surface of the multilayer printed circuit board; an output signal is received from a signal output layer with one intermediate layer of the multilayer printed circuit board acting as the signal output layer; the frequency of the input signal is adjusted, and the first frequency of the input signal corresponding to the minimum amplitude of the output signal is recorded; and the dielectric constant of the multilayer printed circuit board is calculated according to the first frequency of the input signal and the first distance between the intermediate layer and the second external surfac