Sepsis is a systemic inflammatory response syndrome caused by infection, with high fatality rate and complex pathogenesis. Early and accurate diagnosis is essential to improving the prognosis of patients with sepsis. This review briefly describes the basic pathogenesis of sepsis, and summarizes the current new technologies for detecting sepsis from two aspects: pathogen detection and host immune status detection, such as digital polymerase chain reaction, biosensors, fluorescent probes, single-cell RNA sequencing, and enzyme-linked immunospot assay. By comprehensively analyzing and applying these new techniques, it is helpful to improve the efficiency and accuracy of early diagnosis of sepsis and improve the clinical treatment effect of patients.