Objective To study the clinical types and the characteristics of the meconium aspiration syndrome (MAS). Met hods According to the symptoms and signs, results of chest radiograph and d oppler ultrasonic echocardiograph, 100 cases of MAS were divided into 5 clinical types. All cases were divided into 3 clinical types based on the severity of th e diseases. Results The 5 typess were: asymptomatic, general, p ersistent pulmonary hypertension of the newborn (PPHN), the acute respiratory di stress syndrome (ARDS) and pulmonary hemorrhage. The number of cases (and rate) of each type was 18(18%), 70(70%), 6(6%), 3(3%) and 3(3%) respectively, and the mortality rate of each type was 0, 1.4%, 16.7%, 33.3% and 66.7% respectively. The cases (and rate) of the mild type, severe type and risky type were 64 (64%), 23 (23%) and 13 (13%) respectively. The mortality rate of each ty pe was 0, 4.3% and 30.8%. Conclusions The division of c linical types of MAS may be useful in the treatment and prognosis.