【Abstract】 Objective Neutrophil/lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR) are two emerging serum inflammatory markers, which have been extensively studied in the cardiovascular diseases in recent years. The purpose of this study was to explore the relationship between NLR and PLR and DCAS, and study the assistant diagnostic value of NLR and PLR in DCAS. Methods This study retrospectively reviewed 64 patients with DCAS diagnosed by transthoracic echocardiography in the hospital from January 2012 to December 2018. According to the transaortic mean pressure gradient, 31 patients were classified into the mild to moderate AS group (transaortic mean pressure gradient＜40mmHg), and 33 patients were classified into the severe AS group (transaortic mean pressure gradient≥40mmHg), and 36 healthy people visited the hospital at the same period were selected as observation group. The clinical data, ultrasound and laboratory tests of patients were collected. NLR and PLR were calculated. The value of NLR and PLR in DCAS patients was evaluated by receive operating characteristic (ROC). Results Compared with the observation group and mild to moderate DCAS group, the NLR of severe DCAS group was significantly high (4.40±1.68 vs3.36±1.08 vs 2.08±0.75，P＜0.001). The PLR of severe DCAS group was also significantly higher than that of control group and mild to moderate DCAS group (191.69±58.00 vs165.41±4.93 vs123.72±46.17，P＜0.001). NLR and PLR were positively correlated with transaortic mean pressure gradient (r=0.493, P＜0.001; r=0.301, P＜0.016). When using a cutoff point of 4, NLR diagnoses the DCAS with a sensitivity of 89% and a specificity of 78% (ACU=0.880, 95%CI:0.812-0.947, P＜0.001). When using a cutoff point of 140, the PLR diagnoses the DCAS with a sensitivity of 79% and a specificity of 66% (AUC=0.801, 95%CI: 0.711-0.892, P＜0.001). Conclusion NLR and PLR are related to the severity of DCAS, and NLR and PLR can be used as serum inflammatory markers to assist the diagnosis of DCAS.