An ultra-wideband radar transceiver and an operating method thereof are provided. The ultra-wideband radar transceiver includes a receiving module. The receiving module includes an I/Q signal generator, a first sensing circuit and a second sensing circuit. The I/Q signal generator receives M consecutive echo signals and generates M consecutive in-phase signals and M consecutive quadrature-phase signals accordingly, wherein M is an integer greater than 1. The first sensing circuit is coupled to the I/Q signal generator to receive the M consecutive in-phase signals and is configured to perform integration and analog-to-digital conversion on the M consecutive in-phase signals to generate a first digital data. The second sensing circuit is coupled to the I/Q signal generator to receive the M consecutive quadrature-phase signals and is configured to perform integration and analog-to-digital conversion on the M consecutive quadrature-phase signals to generate a second digital data.