Starting from the relations between entries of block pulse operational matrices, block pulse regression equations corresponding to the original differential equation models with time-varying parameters are obtained. Based on simple forms of the regression equations, algorithms developed in discrete-time model identification can be applied directly to estimate the time-varying parameters of the continuous models without much modification. Compared with other identification methods for the same problem, this new method is simple, and can be applied to both batch and recursive estimations of continuous time-varying linear systems from their sampled input and output data by means of digital computers.