A method for separating luminance and chrominance of a composite TV analog signal includes the steps of: measuring first differences between horizontal neighbor pixels, second differences between vertical neighbor pixels and third differences between temporal neighbor pixels encoded in the composite TV analog signal; comparing the first, second and third differences with one another to obtain a minimum difference used as a factor of a weighting function; and filtering the composite TV analog signal simultaneously by a two-dimensional (2D) comb filter and a three-dimensional (3D) comb filter according to the weighting function on the basis of the minimum difference to obtain a luminance signal and a chrominance signal, in which magnitudes of a part of the composite TV analog signal filtered by the 2D comb filter and magnitudes of the other part of the composite TV analog signal filtered by the 3D comb filter are determined by the weighting function.