The estimate of human respiration-rate using radar is used to detect the enemy force or the terrorist, to search a life trapped under the debris, to assess continuously a patient’s respiration and so on. The conventional scheme for the estimation of human respiration-rate using Ultra-wideband(UWB) impulse radar is based on the magnitude of the reflected signal from the human. The conventional scheme works well in high signal-to-noise(SNR). However, as the SNR decreases, the detection probability of the conventional scheme decreases because the noise interferes with the reflected signal from the human. In this paper, the novel method to estimate the human respiration-rate based on the energy signal is proposed for UWB impulse radar system. Experimental results show that the proposed scheme has higher detection probability than the conventional scheme in low SNR.