A novel surface-enhanced Raman scattering (SERS)-active substrate based on Au nanoparticles (AuNPs)-coated silver nanowire (AgNW) is obtained by an effective and simple method. The results show that the hybrid structures prepared by this method are powerful SERS-active substrates for the detection of malachite green (MG) molecules with the limit of 1 nmol/L. The excellent enhancing ability mainly comes from two kinds of hot spots. One is from the gaps among the adjacent AuNPs, and the other is the presence of zone between AuNPs and AgNW. In particular, the AuNPs-coated AgNW can be viewed through the objective of the confocal Raman spectrometer due to the length of the AgNW reaches microns, which can improve the repeatability of detection. Moreover, it is of great significance in research of SERS mechanism and application.