A new data processing system used in radioimmunoassay is reported. Based on the latest mathematical model recommended by WHO
the system includes 4- and 5-parametey logistic models and 4-parameter single binding site mass action model.A new approach tO the curve fitting of RIA has been developed based on the combination of the direct searching in the optimization method and the traditional non-linear regression. The system also possesses perfect quality controling and database function .