Technology Acceptance Model establishes a casual relationship between its constructs namely, system design features, perceived usefulness (PU), perceived ease of use (PEOU), attitude towards using a system and the actual usage of the system. In evaluating at the user acceptance of the technological systems the model offers informative representation. In this review the evolution of Technology acceptance model is going to be looked at extensively. Chuttur (2009, p.1) explains that the model has become important in predicting the system user acceptance. Indeed, this writer continues to argue that for anyone looking at the user acceptance of the technology it is imperative for him or her to have a good understanding of TAM. Having originated from the Theory of Reasoned Action this theory has also undergone modifications. In this work the word behavior is extensively used and refers to actualization of intention or perceived behavioral control leading to an action. The model became important due to the failure of the systems in 1970’s and it became necessary to predict the system use. Prior to its introduction the earlier work was not reliable in providing measure in acceptance or rejection. Relationships between perceived usefulness, perceived ease of use, attitude and actual system use are also studied.