Abstract: The Richtmyer-Meshkov instability (RMI) occurs widely in man-made applications such as inertial confinement fusion, supersonic combustion, and weapon implosion, and thus has become an important research topic over recent decades. A key element for experiments on RMI is the interface formation. In this manuscript, a novel soap-film technique is adopted to generate well-characterized single-mode air/SF₆ interfaces. A planar shock tube in University of Science of Technology is improved by placing a solid wall at the tail end such that a reflected shock wave is created when the incident shock arrives there. In this way, the experimental study on the RMI at a single-mode interface impacted successively by the incident and reflected shock waves is realized. Detailed structures of the evolving interface and wave patterns are captured by a schlieren system combined with the high-speed imaging technique. Special attention is paid to the effect of reflection distance (defined as the distance between the initial interface and the end wall of shock tube) on the instability development. It is found that the post-reshock growth rate of perturbation amplitude keeps nearly constant while increasing the reflection distance within a certain range. When the reflection distance exceeds a certain value, the post-reshock growth rate decreases. This is ascribed to two factors: 1) for large reflection distance cases, the interface becomes rather distorted with numerous small-scale vortices before the arrival of a reflected shock and also exhibits visible three-dimensionality; 2) during the passage of a reflected shock across a large-amplitude interface, shock-shock interaction occurs and produces considerable pressure disturbance, which further affects the instability development. By comparing the measured growth rate with theoretical prediction, we find that both Mikaelian and Charakhch'an models (with appropriate empirical coefficient) are able to give a reasonable prediction of the post-reshock growth rate. It is also found that the empirical coefficient in each model is sensitive to the interface status immediately before the impact of reflected shock.