Abstract: The relationship between continuous cropping obstacles and accumulation of pathogens in rhizospheric soil was evaluated, and the mechanisms of continuous potato cropping obstacles explored, using an optimized SYBR Green I dye real time fluorescent quantitative PCR approach. The methods were used to perform quick checks and quantification of Fusarium sambucim and F. solani in soils infested with potato Fusarium dry rot disease and to investigate the dynamic changing trends of F. sambucim and F. solani in rhizospheric soil of continuously cropped potato. The concentration of primers was 0.4 μL (10 mmol/L), of DNA template was 3 μL, and the annealing temperature was 60℃. With an increase in years of continuous cropping potato, the numbers of F. solani and F. sambucim in rhizospheric soil showed an upward trend. The largest amount (1.45×10⁴ copies/g) of F. solani accumulated during the squaring period of five years and it increased 27.8 times compared with the control group (CK). F. solani cumulants CP4, CP3, CP2, CP1 were more than those of RP and increased by 11.4, 35.5, 6.9 and 2.8 times respectively. The largest amount of F. sambucim cumulants (2.21×10⁴ copies/g) was also during the squaring period of five years and compared to the CK they increased 25.0 times. The F. sambucim cumulants CP4, CP3, CP2, CP1 were more than those of the CK and increased by 10.5, 16.31, 8.32 and 3.51 times respectively. Accumulation of rhizospheric Fusarium may be one of the main reasons for the occurrence of obstacles to continuous potato cropping.