Abstract: Abstract:Pseudo static model updating method is presented to reduce the algorithmic complexity in dynamic model updating process. With characteristic force concept, a dynamic model is transformed into a static model to update, and Eigen analysis is avoided. Spline interpolated method is adopted to match measured messages with computed ones. Using complex variable differential method, an efficient parameter sensitivity analysis technology is developed. Statistic formula also is constructed to calculate the errors in model updating process. With numerical verification, the developed method is efficient and reliable for model updating. As a case study, the model of the Run Yang Bei-Cha Yangzi cable stayed bridge tower is updated with the pseudo static model updating method. With the updated parameters, the computed results of the bridge tower coincide well with the measured ones.