Abstract: Convolution technique applied to analyzsis a linear time-invariant system (LTIVS)in time domain is discussed.It is shown that the kernel of characteristic analysis of all LTIVS in time domain is to compute the convolution of its input excitation with the system's impulse response.Moreover,convolution can be used to analyze the zero-input response and total response of a LTIVS as well as to analysis the impulse response and zero-state response of the system.