Flow-induced vibration (FIV) is of both fundamental and practical significance and is ubiquitous in marine and offshore engineering, including chimney stacks, suspension bridges, subsea pipelines, risers and transmission pipe series in chemical plants, etc. FIV of two tandem cylinders is a crucial consideration in designing and constructing cylindrical structure in modern engineering. The experiments are carried out in a low speed wind tunnel with an elastically mounted circular cylinder in the wake of another smaller fixed cylinder that made of stainless steel. Vibration amplitude, lift force, added mass, added damping and flow structure surrounding the cylinders are measured. It has been found that the FIV of the elastic cylinder is affected by both L/d and e*, thus confirming the proper arrangement to get rid of the violent vibrations.