In this work,a microfluidic device for kinetic study of oligonucleotide and protein interaction was developed based on a highly selective luminescent switch-on probe.The luminescent probe is a G-quadruplex-selective luminescent iridium(Ⅲ),which is specially bind to the VEGF165 oligonucleotide,and is applied as a convenient biosensor for label-free quantitative analysis of VEGF165 protein in the designed microfluidic platform.The microfluidic device utilizing principles of hydrodynamic focusing and diffusive mixing was fabricated to monitor the process of protein-oligonucleotide interactions.The kinetics studied on a microfluidic device enables for rapid exchange and mixing of samples from milliseconds to minutes.As a result,different transient states during kinetics process were monitored and recorded.Moreover,quantitative analysis of VEGF165 from cell metabolism was established.Furthermore,the combination of microfluidic technique and G-quadruplex luminescent probe will be potentially applied in the studies of intramolecular interaction and molecule recognition in the future.