Disclosed herein are a Layered Division Multiplexing (LDM)-based broadcast relay apparatus and method. The LDM-based broadcast relay apparatus includes a first layer symbol generation unit for outputting a first layer broadcast signal based on a received Layered Division Multiplexed (LDM) broadcast signal, a data buffer unit for storing the received LDM broadcast signal for a delay time before the first layer broadcast signal is output, and a second layer symbol generation unit for outputting a second layer broadcast signal by eliminating the first layer broadcast signal from the stored broadcast signal.