Abstract: The current codes for calculating the shear capacity of internal reinforced concrete frame joints are simi-empirical and semi-theoretical. Due to limited test data and the discretized characteristics of concrete structures, the design equations recommended in the code is lack of a clear theoretical framework. Thusly, the concept of dynamic information updates based on the Bayesian approach was introduced. 101 groups of experimental test results of internal frame joints were collected from experience at home and abroad. A multivariate linear probabilistic shear strength model for reinforced concrete internal joints was established using the Bayesian estimation method. Subsequently, the model was simplified using the stepwise procedure to remove parameter insignificant explanatory terms. The developed probabilistic model is compared with experimental results and design equations proposed by ACI 352R-02. It indicated that the proposed model inherits the completeness of prior models and the accuracy of experimental data information, and therefore is recommended for the shear strength calculation of the interior joints of reinforced concrete frames.