In order to realize low distortion acquisition and processing for wideband radar signal in the wideband radar system, a wideband and low spurious sampling system with amplitude and phase correction is studied and designed. The system uses the implementation scheme of wideband analog to digital converter (ADC) device and high performance field programmable gate array (FPGA) device, which is researched from low jitter sampling clock, low noise power, anti crosstalk for the optimal low spurious performance. To improve the band transmission characteristics of the system, a finite impulse response(FIR) filter is designed based on optimization algorithm. Finally, the designed system is tested in lab, and the experiments results prove that the spurious-free-dynamic-range (SFDR) of the system is characterized as -50 dBc worst-case over an instantaneous bandwidth of more than 800 MHz, sampling rate of 1.8 GS/s, quantization length of 8 bits. System performance levels meet the application requirements of wideband radar signal acquisition, wideband radar target imaging and wideband radar target echo reconstruction.