Irregular soft tissue density shadow on the lung is an imaging description, most of the soft tissue density is pathologically altered, which can be caused by a variety of factors, such as pneumonia, tuberculosis, lung tumors and so on. 1. Pneumonia: Pneumonia can be caused by fungal, bacterial, viral infections, etc. Patients may have irregular soft tissue density shadows on the lungs, which are usually accompanied by fever, cough and other symptoms, and the diagnosis can be confirmed by inflammatory index test and pathogenicity test. 2. Tuberculosis: Tuberculosis is caused by Mycobacterium tuberculosis infection, and the foci of the disease may appear as irregular soft tissue density shadow on the image. 3. Lung tumor: Lung tumor can be divided into benign tumor and malignant tumor, if the size of benign tumor is less than 8mm, no discomfort symptoms can be regularly rechecked, if the benign tumor is larger or with discomfort symptoms, it is recommended to surgical resection; if the malignant tumor is recommended to surgical resection, if necessary, combined with radiotherapy, chemotherapy, immunotherapy, targeted therapy and other treatment methods. Determination of benign and malignant tumors can be determined by puncture biopsy or resection of the lesion and sent to pathology. When irregular soft tissue density shadow appears on the lungs, it should go to the hospital in time to find out the cause of the disease and carry out the treatment.