A mattress with airflow-circulating function has a main body and a ventilator. The main body has a crisscross groove formed in the main body. The ventilator is detachably connected with the main body and has a hollow joint, four extending tubes and a curved tube. The joint has five openings. The extending tubes are respectively and securely connected to four of the openings of the joint to form a cross and are mounted in the groove. Each extending tube has multiple apertures formed in the extending tube. The curved tube is securely connected to the other one of the openings of the joint and is mounted through the main body. Accordingly, air can be pumped into the joint and is ejected out from the apertures toward the part of the human body. Therefore, the circulating airflow can massage the part of the human body, relieve the pressure and facilitate blood circulation.