The invention discloses a reagent for liver cancer diagnosis, a kit, a detection method and application. The reagent for liver cancer diagnosis comprises PCR (Polymerase Chain Reaction) primer pairs which aim to at least two of an NEBL gene, an FAM55C gene, a GALNT3 gene and a DSE gene of genome DNA and comprise methylated cytosine. By adopting the reagent, six areas with methylated cytosine on four genes are subjected to conjoint analysis as biomarkers for judging liver cancer pathogenesis and reoccurrence risk, the accuracy of the biomarker is far greater than that of detection of a single biomarker, and false positive is reduced. In addition, the reagent has the advantages of being convenient in material taking, low in cost, high in sensitivity, good in stability and the like, the pathogenesis and reoccurrence risk of cancer liver can be precisely detected in time, great clinical application values can be achieved for rapid diagnosis on early-stage cancer liver, and further researchon rapid diagnosis kits for patients suffering from early-stage liver cancer is technically ensured.