A robot which is capable of odour plume tracing can be employed in many applications, such as the detection of toxic gas, fire at its early stage and explosives. In this study, a small size indoor plume-tracing mobile robot was aimed to be developed to demonstrate how simple and basic insect-like robotic system can localise an odour source in a wind-varying indoor environment. The robot adopted the anemotaxis plume-tracing algorithm and the wall-following collision avoidance algorithm to trace plumes in an obstructed environment. Experimental results have demonstrated the capability of this kind of plume-tracing mobile robot.