【Abstract】 Objective To learn the infection status of Lyme disease in Diebu county, the change of natural focus and the situation of the host infected by Lyme disease. Methods The antibody of Borrelia burgdoferi in the crowd serum was detected by immunofluorescence, and the spirochete DNA was tested with PCR. Results A total of 522 serums were sampled from the people in 5 forestry centres and 7 villages of Dieby county, and the antibodies of B.burgdoferi were positive in 57 serums with the positive rate of 10.92%. Sixty nine species of rat-shapes were captured, and the average capture rate was 15.33%. Among them, there were 25 Niniventer confucianus Hodgsons,18 Rattus norvegicus Berkenhouts, 15 Apodemus specious Temminck, 9 Apodemus specious Linnaeus, 1 Mus musculus and 1 Apodemus agrarius Pallas, which accounted for 36.23%, 26.09%, 21.74%, 13.04%, 1.45% and 1.45%, respectively. Six spleens and five kidnies were positive in 62 rats?spleens and 66 rat-kidnies, and the positive rate was 15.15%（10/66）. The positive samples included  6  R.niviventer  Hodgsons,  2  R.norvegicus  Berkenhouts, 1 A.specious Temminck and 1 A.specious Linnaeus three strains of B.burgdoferi were isolated from rats kidnies and bladders with BSK culture medium. Conclusion The natural foci of Lyme disease were widely distributed in Diebu county, and the infection rate in the crowd was higher.