The system of signal acquisition and processing in industrial CT can transfer analog signals outputted by X-ray linear array detector into digital signals and transmit them into computer after uniformity in order to supply data for the image reconstruction of measured object, which plays an important part in CT. This paper designs a system that can do parallel acquisition and processing for four differential signals based on FPGA+ARM processing architecture. It designs signal conditioning circuit and A/D circuit to achieve parallel acquisition of pixel signal with high speed. Besides, it reaches two-point calibration method by FPGA to do uniform calibration on pixel. And ARM transfers data into computer through network. This experiment indicates that systematic acquisition is quick with the result of the raising of CT scanning speed; the uniformity of pixel has good effect and the image uniformity is improved obviously.