The invention relates to a nested PCR detection method for Ralstonia solanacearum in peanuts, which uses sample DNA as a template, uses bacterial 16S-23S rDNA ITS sequence general primer L1 / L2 to carry out the first round of PCR amplification, and then uses the first round of PCR product As a template, a pair of specific primers W1 / W2 designed to identify R. solanacearum was used to carry out the second round of PCR amplification, and the amplified product was detected by electrophoresis. If a specific band of 374bp appeared, the pathogenic bacteria detected For peanut Ralstonia solanacearum. The nested PCR detection method for R. solanacearum of the present invention has a detection sensitivity of 10 fg to the pathogen genome DNA, and can overcome the shortcomings of methods such as biological identification, ELISA and conventional PCR, and provides a fast, sensitive, The specific detection method of peanut R. solanacearum can be used for early diagnosis of peanut R. solanacearum in the field, which is of great significance for the early detection and timely control of the disease.