Objective To investigative the value of strain ultrasound elastography in the diagnosis of subpleural pulmonary lesions (SPLs). Methods 170 patients with SPLs in our hospital from June to December 2019 were analyzed retrospectively, including 84 (49.41%) benign and 86 (50.59%) malignant. The SPLs were scored by the traditional elastography 5-score method and improved elastography 5-score method, respectively. The diagnostic abilities of the two methods were compared by the receiver working characteristic curve, sensitivity, specificity and accuracy. Results The elastic score obtained by traditional 5-score method was as follows. Benign group: 1 score, 2 (2.38%); 2 scores, 15 (17.86%); 3 scores, 42 (50.00%); 4 scores, 24 (28.57%); 5 scores, 1 (1.19%). Malignant group: 1 score, 0 (0%); 2 scores, 5 (5.81%); 3 scores, 8 (9.30%); 4 scores, 35 (40.70%); 5 scores, 38 (44.19%). The elastic score obtained by the improved 5-score method was as follows. Benign group: 1 score, 45 (53.57%, water wave sign 43 cases); 2 scores, 9 (10.71%); 3 scores, 20 (23.81%); 4 scores, 9 (10.71%); 5 scores, 1 (1.19%). Malignant group: 1 score, 2 (2.33%, water wave sign 2 cases); 2 scores, 4 (4.65%); 3 scores, 8 (9.30%); 4 scores, 35 (40.70%); 5 scores, 37 (43.02%). The proportion of water wave sign in benign group was significantly higher than that in malignant group (51.19% vs 2.32%, c_² = 49.65, P < 0.001). The diagnostic ability evaluation indexes of the traditional and improved score method were as follows: the area under the receiver working characteristic curve was 0.832 vs 0.914 (Z=3.597, P < 0.001), the sensitivity was 74.49% vs 87.80%, the specificity was 81.94% vs 84.09%, and the accuracy was 77.65% vs 85.88%. Conclusion The strain ultrasound elastography has a good ability of differential diagnosis of benign and malignant SPLs, and the improved elastography score method is better than the traditional score method.