【Objective】 To study the value of neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) in the diagnosis and prediction of disease severity in adolescent atopic dermatitis (AD). 【Methods】 A total of 100 AD patients and 50 healthy individuals were selected from Dermatology Department of our hospital.The age, gender, blood routine results of all subjects were collected, and NLR and PLR were calculated.The diagnostic value of NLR and PLR for AD and severe AD was discussed by receiver operating curve (ROC), the relationship between NLR, PLR and the risk of AD was analyzed. 【Results】 The AUC of NLR and PLR in the diagnosis of AD was 0.780 and 0.769, with the best cutoff value at 2.95 and 98.50 respectively, and no significant difference in the predictive value between NLR and PLR was noticed (P>0.05). The proportion of NLR≥2.95, PLR≥98.50, red blood cell distribution width (RDW), mean platelet volume (MPV), white blood cell count (WBC) and eosinophils (E) in AD group were significantly higher than those in control group (all P<0.05). Before and after adjusting for confounding factors, the odds ratio (OR) of patients with NLR≥2.95 and PLR≥98.50 were 12.250 vs 6.048 and 5.525 vs 4.352, respectively.NLR, PLR and E in mild AD group were lower than those in severe AD group, and NLR and E in moderate AD group were lower than those in severe AD group, the differences were statistically significant (all P<0.05). The AUC of NLR and PLR in diagnosis of severe AD was respectively 0.712 and 0.675, the difference was statistically significant (P<0.05). NLR, PLR, RDW and E were positively correlated with SCORAD score, and the r values were 0.254, 0.198, 0.202 and 0.219 respectively. 【Conclusion】 The increase of NLR and PLR were the risk factors of AD, and had certain diagnostic value for AD and severe AD.