Objective A new technique of transthoracic lung ultrasonography (TLS) has emerged and demonstrated promising results in acute heart failure diagnosis at an early stage. However, the diagnostic value of ultrasound lung comets (ULCs) for acute heart failure (AHF) performed in busy emergency department (ED) is uncertain. The present meta-analysis aimed to assess the diagnostic efficiency of ULCs in AHF. Methods We conducted a search on online journal databases to collect the data on TLS performed for diagnosing AHF published up to the end of July 2017. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and summary receiver operating characteristic (SROC) curve were calculated. The post-test probability of AHF was calculated by using Bayes analysis. Results We enrolled a total of 15 studies involving 3,309 patients. The value of sensitivity, specificity, PLR, NLR, DOR, area under the SROC curve, and Q* index was 85%, 91%, 8.94, 0.14, 67.24, 0.9587, and 0.9026, respectively. We detected significant heterogeneity among included studies, and therefore, all these results were analyzed under the random-effect model. We also explored possible sources of heterogeneity among the studies by using meta-regression analysis. Results suggest that the time interval between patient's admission to bedside TLS examination was closely related to TLS accuracy. Conclusion This meta-analysis demonstrated that detecting ULCs is a convenient bedside tool and has high accuracy for early AHF diagnosis in ED. TLS could be recommended to be applied for early diagnosis of AHF in ED.