Proteomics demands high resolution multidimensional separation techniques due to its extremely high complexity.Over the past twenty years,various multidimensional separation strategies have been developed and of which,interface technology is the core technological challenge in securing very high resolution.Droplet microfluidics provides series of unique advantages in manipulating small-scale samples,such as micro-volume operation,limited diffusion and none cross-contamination,therefore has the potential to be an ideal interface strategy for two dimensional separations.In this study,droplet technology was utilized as a novel interface solution in combining high performance liquid chromatography and capillary electrophoresis.Based on microchips of different structures,functions such as "droplet generation" and "oil depletion" can be realized,through which,samples can be effectively transferred between two dimensions.Using protein digests as sample,the two dimensional HPLC-CE system provided high resolution separation with a peak capacity over 3000,which clearly demonstrated feasibility of droplet interface technology as well as its potential application in proteomics.