Surface-enhanced Raman spectroscopy (SERS) as a powerful analytical tool has gained extensive attention. Despite of many efforts have been devoted to design SERS substrates, it still remains a grand challenge for creating a general substrate with high SERS active by a simple, controllable and low-cost way. Herein, we attempt to address this issue by fabricating SERS-active nano gold film based on selfassembly chemical plating composite method. The influence of gold colloid particle size on gold seed distribution density and the influence of the particle size of nano gold films on the SERS activity were investigated in detail. 10(-5) M Rhodamine 6G (R6G) was taken as Raman probe molecules and homemade Raman detection microsystem was used as detector. According to the results of SERS detection, the SERS substrate enhancement factors (SSEF) were calculated, and the nano gold film with average particle size of about 55 nm showed the maximum SSEF of 0.93 x 10(5), which indicated such nano gold films showed excellent SERS activity. Moreover, these nano gold films are all low-cost and easy to prepared. This study provided theoretical and experimental basis for the design and preparation of general SERS substrate. (C) 2015 Elsevier B.V. All rights reserved.