The present invention provides a block-based principal component analysis transformation method and a device thereof. The principal component analysis transformation method includes: obtaining an input signal; dividing the input signal and obtaining a plurality of one-dimension vectors corresponding to the divided input signal, wherein a number of the one-dimension vectors is a division number; after arranging the one-dimension vectors to a two-dimension vector, subtracting an average value of the one-dimension vectors of the division number to obtain a zero-mean vector; calculating a covariance matrix of the zero-mean vector; calculating an eigenvector of the covariance matrix; multiplying the zero-mean vector by the eigenvector to obtain a projection coefficient.