A method for analysis of sampled-data feedback control systems with finite pulse width is presented in this work. The analysis is based on introducing a new technique with some approximations by the theories of the Periodically Interrupted Electric Circuits. The results make it possible to obtain the transient and steady-state response of such systems containing a sampler with any pulse width. Furthermore, by utilizing this method, the stability criterion is readily developed and its application to systems under consideration make clear the effects of the sampler with finite pulse width on the performance of sampled-data feedback control systems, which are of considerable importance in view of its engineering applications. Some illustrative examples are given to clarify the method involved and its numerical results are presented to show the performance of the system dynamics. Moreover the results in this investigation are examined by the simulation of the control system in question by means of the analog computer