The apparatus and the method for estimating a channel of a wireless power transmission system using an intelligent reflecting surface according to the exemplary embodiment of the present disclosure check a strength of a received signal received by a terminal with respect to a measured signal transmitted from the transmitter, regardless of the number of reflective elements of the intelligent reflecting surface (IRS) or the number of terminals and estimate a channel between the transmitter and the intelligent reflecting surface (IRS) and the channel between the intelligent reflecting surface (IRS) and the terminal so that the channel information can be efficiently acquired even in the wireless power transmission system including a low power terminal.