Abstract: The fundamental idea of a new model of computing, that is, an interactive model of computing, is introduced. Algorithm, Turing machine and Church’s thesis have been regarded as the theoretical foundation of computing ever since. But computer technologies have changed so rapidly that the gulf between them becomes wider and wider. The algorithm and Turing machine can’t play a role of theoretical paradigm of computing science any longer. This fact leads to a new interactive model of computing, which is an extension to algorithm and more expressive than algorithm.