Abstract: The monodisperse water-in-oil microdroplets were prepared by a flow-focusing microfluidic chip.The capture effciency and operating performame of three different encapsulation structures were compared.A circular structure with opening up and down was selected for better encapsulation of microdroplet.Further,single cell encapsulation in microdroplet,cell staining and cell viability were carried out using this chip.Under the optimum conditions,monodisperse microdroplets with radius of 75 μm were prepared,the encapsulation of microdroplet in chip and single cell in each droplet were 100% and 33%,respectively.Also,staining results of single cell in capture droplets showed that the cell nucleus staining in microdroplets was accomplished within 5 min cell.The viability of cells in droplets was evaluated directly via live-dead staining in real time.