Detection oriented UWB wireless sensor node places several stringent requirements on compatibility, power consumption and implementation cost. The compatibility requirements mandate the digital realization by using high speed analog-to-digital converter (ADC). However, the need of full resolution, extremely high speed ADC contradict to the application demand of low cost and power consumption. Finite-resolution sampling receiver is a practically appealing approach to relax the demand of high-rate ADC. To demonstrate the theoretical feasibility of low-bit sampling technique in target detection, the quantization based detection algorithm is elaborated. The performance characteristics from theoretical values and simulation results are presented for different sampling resolutions; detailed analysis of setting the optimal quantization step are also included. All these results provide useful guidelines for using low-complexity finite-resolution technique in UWB target detection.