Data acquisition system is a measurement tool for people to achieve various functions. The high sampling rate, high throughput and high real-time performance become the inevitable trend. Therefore, the key technologies of improvement are successfully carried out and discussed on the basis of the 2.4 Gsps data acquisition system based on high speed ADC EV8AQ160. And finally, using XILINX K7 series FPGA as processing core, a high sampling rate and high bandwidth DAQ system with DDR3 SDRAM's large capacity cache and PXIe1.0 X4 DMA transmission is implemented. The experimental results show that the highest sampling rate of the upgraded DAQ system is increased to 5 Gsps, the effective upload bandwidth is as high as 455 MB/s.