The invention relates to a power distribution network harmonic impedance calculating method based on canonical correlation analysis. Firstly, a bus voltage instantaneous value at a common connection spot PCC portion where a power grid is connected to a user and an instantaneous value of the current injected by the user into the grid are collected, and a harmonic voltage and a harmonic current canbe obtained through the Fourier transform; then, a fluctuation amount is obtained by using a slip method; the collected harmonic voltage and harmonic current are subjected to slip processing to obtaina harmonic voltage fluctuation amount delta dotted Vpcc and a harmonic current fluctuation amount delta dotted Ipcc; calculating an impedance sample Zpcc; setting the correlation to analyze the convergence condition of the two convergence zones and classifying the impedance sample according to the magnitude of the fundamental current fluctuation at the PCC portion; finally filtering the impedancesamples and using the canonical correlation analysis method to obtain the correlation coefficients of the harmonic voltage fluctuation amount and harmonic current fluctuation amount using canonical correlation analysis method; and according to the size of the correlation coefficients and the judgment conditions, excluding the linearly uncorrelated points, the harmonic impedance on the grid side and the harmonic impedance on the user side can be obtained and the harmonic impedance value can be more accurately estimated.