The main reasons for the hardness of the left side of the abdomen and the pain when pressed are: fecal stasis, intestinal space-occupying lesions and left adnexal masses. 1. Fecal stasis: due to the slow peristalsis of the gastrointestinal tract, a large amount of fecal stasis in the intestinal tract can not be discharged, and in the long run, it will be touched in one side of the abdomen along the intestinal tract to walk along the fecal matter, due to the fecal matter stimulation of the intestinal wall, it may also appear to be painful to press on the symptom. 2. Intestinal space-occupying lesions: such as sigmoid colon tumor, if the tumor is relatively large, it will be touched in the left side of the abdomen with hard lump-like tissues, and due to the tumor’s oppression and pulling on the surrounding tissues, it will also have the symptom of pressing pain. 3. Left adnexal mass: left adnexal mass, such as left adnexal cyst, left adnexal teratoma, left adnexal malignant tumor, etc., when the tumor grows to a certain volume, it will be touched in the left side of the abdomen, and at the same time, due to the pressure and pulling of the surrounding tissues, it will also have the symptom of pressing pain. If the above symptoms are not relieved after defecation, it is necessary to consult a doctor in time to avoid delaying the condition.