Digital polymerase chain reaction (PCR) is an emerging technology for quantitative analysis of nucleic acids, employing the same fluorescence chemistry as quantitative PCR (qPCR) but different mathematical principles to achieve absolute quantification of target nucleic acid sequences, without the reliance on external references such as standard curve. This technology is both conceptually simple and extremely robust in terms of assay performance, including increased sensitivity, precision, reproducibility and repeatability. Digital PCR technology has been widely used in life science research and applications. In the field of medical testing, digital PCR provides accurate quantification of disease-related nucleic acid biomarkers, enabling early diagnosis of diseases, monitoring of disease progression and evaluation of therapeutic efficacy as well. The emergence of digital PCR will push the medical testing into the stage of precise quantification. Here we review the progress and cutting edge of digital PCR technology, especially droplet digital PCR technology in the field of infectious diseases.