The invention discloses a system for estimating the state of a critically ill patient in an obstetrical department, which comprises an input end, an output end and a data processing module. Firstly, measured heart rate, blood pressure, body temperature, breathing rate, pH, blood HCO-3 concentration, oxygen partial pressure, alveolar arterial blood oxygen tension difference, potassium ion concentration, hematokrit, white cell count, platelet count, fibrinogen, glutamic-oxaloacetic transaminase, albumin, bilirubin, creatinine, blood glucose concentration and nervous system grading data are inputthe system through the input end; the data processing module evaluates a death risk factor; and at last, the output end directly reflects the result of the patient and the expert suggestion. The invention can not only accurately evaluate the critical degree of the state of the patient and predict the death risk, but also can provide quantitative indexes for changing to a three-class hospital, andis beneficial to improve the treatment level of the critical state of the obstetrical department and lower the death rate of pregnant and lying-in women and perinatal infants.