Objective: It constructs a method to estimate China's family catastrophic health expenditure from macro data, and tests its accuracy. Methods: Based on the Newton-Cotes algorithm in computational economics, the two-dimensional heterogeneity of household income and medical expenditure is fully considered. On the basis of simulating the ratio of medical expenditure to disposable income of 90000 heterogeneous households, the occurrence rate of catastrophic health expenditure, poverty rate due to disease, occurrence intensity and concentration index of the whole society are estimated. Results: With the growth of China's economy and the improvement of family income, the incidence and intensity of catastrophic health expenditure are decreasing, and the degree of concentration is increasing. Conclusion: It is proved that this method has certain accuracy and stability, which can be used as a supplement and reference to the existing estimation methods.