Objective To discuss the disease spectrum and pathological characteristics of retroperitoneal tumors. Methods The pathological information of 1 050 patients who were diagnosed with "retroperitoneal mass/tumor" by the surgical team led by Dr. FENG Xiang of The First Affiliated Hospital of Naval Medical University (Second Military Medical University) from Jan. 2012 to Dec. 2021 was retrospectively collected, and the proportions of various types of tumors were analyzed, as well as the clinical and pathological features. Results A total of 1 050 pathological specimens were included:407 (38.76%) tumors of mesenchymal origin, including 348 (33.14%) malignant tumors and 59 (5.62%) benign tumors; 211 (20.10%) tumors of neurogenic origin, including 18 (1.71%) malignant tumors and 193 (18.38%) benign tumors; 127 (12.10%) tumors of lymphohematopoietic origin, including 88 (8.38%) malignant tumors and 39 (3.71%) benign tumors; 19 (1.81%) other primary retroperitoneal tumors; 42 (4.00%) malignant tumors of unknown origin; and 244 (23.24%) metastatic tumors. Among the malignant tumors of mesenchymal origin, the most common pathological types were liposarcoma (178 cases, 16.95%), and leiomyosarcoma (54 cases, 5.14%). Conclusion Among retroperitoneal tumors, mesenchymal tumors are the most common, followed by neurogenic tumors, lymphoid hematopoietic tumors and metastatic tumors.