The technique of TaqMan MGB real-time fluorescent PCR was established to detect Diaporthe phaseolorum var.caulivora(DPC) and D. phaseolorum var.meridionalis (DPM). The primers and TaqMan MGB probes were designed based on the ITS of DPC, DPM, D. phaseolorum var. sojae and Phomopsis longicolla. A series of genomic DNA dilution were used to detect sensitivity of the technique, the results showed that the limits of detection for DPM and DPC were 7 fg/μL and 6 fg/μL DNA respectively.