For　improving　the　ability　of　detection　systems　to　identify　partial　discharge　signal　and　interference　signal,　the　Mellin　transform　was　applied　in　PD　signal　process　to　obtain　the　special　pulse　shape　in　frequency-domain　according　to　the　wide-band　characteristic　of　PD　pulse　signal.　A　method　of　calculating　the　fast　Mellin　transform　was　presented　based　on　the　fast　Fourier　transform　(FFT)　for　the　real　signal　in　discrete　time-domain.　The　results　show　that　the　FMT　algorithm　is　simple　with　a　fast-operational　speed　for　on-line　real-time　signal　processing,　which　provides　a　new　method　to　make　the　frequency-domain　transform　and　feature　extraction　for　PD　pulse　signals.