Objective: To evaluate the value of anteroposterior to transverse diameter ratio (A/T) of the thyroid nodule greater than or equal to 1 in diagnosis of its benign and malignant nature. Methods: The studies published before July 2017 evaluating the value of thyroid nodule’s A/T≥1 in diagnosis of malignant lesion were collected through searching several national and international databases. After screening for inclusion criteria, data extraction and quality assessment, the data were analyzed with Meta-DiSc 1.4 statistical software. The heterogeneity among the included studies was assessed, and the pooled effect estimates of thyroid nodule’s A/T≥1 in diagnosing its malignant nature in the included studies were calculated, which included the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), the area under the curve (AUC) of summary receive operating characteristic curve and Q* index. The stability of results of the overall pooled estimates of the included studies was validated by sensitivity analysis, and the sources of heterogeneity among the included studies were analyzed. The publication bias caused by the results of the included studies was evaluated by drawing the Deek’s funnel plot. Results: A total of 13 studies were included, involving 11 243 nodules that included 9 227 benign nodules and 2 016 malignant nodules. The quality of 13 studies was uneven, and there was a heterogeneity caused by non-threshold effect among the included studies (r=0.352, P=0.239). The overall pooled sensitivity, specificity, PLR, NLR, DOR, AUC and Q* index of the included studies of thyroid nodule’s A/T≥1 for diagnosing malignant nodule were 0.31 (95% CI=0.29–0.33), 0.50 (95% CI=0.49–0.51), 1.32 (95% CI=0.81–2.14), 0.85 (95% CI= 0.73–0.99), 1.51 (95% CI=0.77–2.90), 0.538 9 and 0.529 2, respectively. The results of the overall pooled estimates of included studies were stable, and the research methods, racial differences and whether by blind design might be sources of the heterogeneity of the studies. The Deek’s funnel plot showed an asymmetrical distribution of the results, indicating that there was a publication bias caused by the results of the included studies. Conclusion: Thyroid nodule’s A/T≥1 has certain value in differential diagnosis of benign and malignant thyroid nodules. However, its sensitivity and specificity are low, so combined judgment with other imaging signs is necessary.