Objective To assess the clinical value of neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) in diagnosis of ankylosing spondylitis. Methods Eighty patients with ankylosing spondylitis and 100 normal controls from Changhai Hospital, Naval Medical University (Second Militaray Medical University) were enrolled in our study. The fasting venous blood samples were collected in the morning for routine blood examination. The differences of NLR and PLR between the two groups were analyzed. The receiver operating characteristic (ROC) curve was used to evaluate the sensitivity and specificity of NLR and PLR, and combined diagnostic test was performed. Results The levels of NLR and PLR in ankylosing spondylitis patients were significantly higher than those in the control group (2.25[1.66, 3.35] vs 1.50[1.23, 2.09], P<0.01; 147.94[104.11, 188.80] vs 105.75[89.55, 148.02], P<0.01]. ROC curve analysis showed that the area under curve (AUC) of NLR in diagnosis of ankylosing spondylitis was 0.694 (95% confidence interval[CI]:0.615-0.772, P<0.01), and the sensitivity and specificity of NLR were 77.5% and 58.0%, respectively, when the cut-off value was 1.64. The AUC of PLR in diagnosis of ankylosing spondylitis was 0.662 (95% CI:0.580-0.756), and the sensitivity and specificity of PLR were 66.2% and 63.0%, respectively, when the cut-off value was 120.91. The sensitivity and specificity of NLR and PLR parallel testing (NLR/PLR) were 83.8% and 50.0%, and the sensitivity and specificity of the NLR and PLR tandem testing (NLR+PLR) were 61.2% and 75.0%, respectively. Conclusion NLR and PLR both have clinical value for the diagnosis of ankylosing spondylitis, and the combination of the two can improve the diagnostic sensitivity and specificity.