Add two mutually immiscible liquids to the microfluidic chip channel, and disperse the dispersed phase into the continuous phase in the form of tiny volume units (10fL-10nL) and extremely fast speed (100-10000 pieces/second) , droplets used as microreactors or trace biochemical sample carriers can be formed. Microfluidic chip droplets have been considered the most important microreactor to date, providing a platform for rapid ultra-large-scale, ultra-low-content reactions at the single-molecule and single-cell levels. At present, the main industrial application of droplet microfluidic technology is the digital PCR nucleic acid quantitative analysis platform.