Digital PCR(dPCR) assay is a highly sensitive absolute quantitative analysis technique for nucleic acids. Digital PCR systems perform amplification by equally dividing the reaction mixtures into a large number of independent reaction units, and calculates the nucleic acid copy number based on the Poisson distribution and the positive ratio. With the advantages of high sensitivity, accuracy and tolerance, digital PCR assay enables absolute quantitative analysis of samples. In recent years, with the maturity of microfluidic technology, digital PCR assay based on microfluidic technology has been rapidly developed, and widely applied in the analysis of gene mutation, copy number variation, viral microbial, genetically modified foods and DNA sequencing. In this article, the principle, development and applications of the digital PCR technique are reviewed.