Cell migration is an early-stage and critical step for cancer metastasis. The most common approach to monitor this process is wound-healing assay. However, this traditional method has some unavoidable limitations. We observed that simply scratching the monolayer of cultured cells might cause local cell damage around the injury line. The cells along the scratched border seemed to be irritated and exhibited abnormal distribution of cytoskeleton reassembly with protruding "cell islands" and "pseudopodia" during wound healing, which might potentially affect the assessment of cell migration behavior. Herein, we applied a microfluidic device that mechanically constrained cells seeded in a designed pattern inside microchannels, and monitored cell movement in a way of mimicking the natural microenvironment of cancerous tissues. We illustrated the capacity of this simple method to probe cellular migration behaviors and to screen some biological active agents that reflected in their influence on cellular motility.