Abstract: A total of 489 lactating cows in Ulanqab were selected in the present investigation. Detection and analysis of the subclinical ketosis of dairy cattle were performed through testing ketone in mine and milk by the ketone body powder method. The results showed that the incidence rate of subclinical ketosis in Ulanqab lactating cows was 10.63 %; the subclinical ketosis incidence rate in the first and second months of lactation was significantly higher than that of the third months of lactation and the after months; the highest morbidity of subclinical ketosis presented in 3 - 5 parity; the morbidity of cows with daily milk production more than 30 kg was higher than that cows with daily milk production less than 30 kg; the morbidity of subclinical ketosis in the large-scale cattle farms was higher than others.