State detection method, apparatus and system of distribution terminal analog input channel

The invention relates to a state detection method, apparatus and system of a distribution terminal analog input channel. The state detection method of the distribution terminal analog input channel comprises the following steps: obtaining multipath analog signals from the analog input channel of a distribution terminal; by use of a Fourier algorithm, respectively calculating a real portion and a virtual portion of each analog signal, and according to the real portions and the virtual portions, calculating fundamental wave amplitude corresponding to each analog signal; calculating effective values of the analog signals through a root mean square method; respectively calculating differences between any one fundamental wave amplitude and the effective values, and determining whether each difference is within a set scope; if the differences are within the set scope, determining that the state of the analog input channel is normal; and if any one difference is not within the set scope, determining that the state of the analog input channel is abnormal. The accuracy of a detection result can be effectively improved.