Under incident light 514.5 nm, Raman scattering spectrum of trace contraband Heroin on finger with low concentration was investigated. It has been known that contraband Heroin has strong fluorescence background in its Raman scattering under visible excitation. By analyzing the sample surface and applying appropriate experimental method, the high signal-noise ratio quality and low fluorescence Raman spectrum was obtained. The result indicated that it would be much improved the Raman scattering spectrum by using slick Al slice as gasket for drugs and selecting proper area on the sample surface, controlling the incident light power. This work could provide a powerful method for detecting trace materials including drugs, explosives, deleterious material in forensic science.