In ultra-wideband (UWB) channels, the signal energy in the acquisition receiver spreads over correlator outputs due to rich multipaths, making the output of each correlator have only a small portion of the total energy. To enhance the acquisition performance for UWB signals by exploiting the signals spread over a number of correlator outputs, this paper proposes a two-stage acquisition scheme. In the proposed scheme, decision variables are formed by combining a multiple of correlator outputs, allowing it possible to make use of the signal energy spread over the outputs jointly. Simulation results show that the proposed scheme can provide a gain of about 0.6dB over the conventional schemes in various UWB channel environments.