The lowpass filter in the CCD readout circuit inevitably results in information distortion of pixel crosstalk while improving the system signal-to-noise. To solve the information distortion caused by the pixel crosstalk in the CCD readout circuit, the relation between the information distortion and the cut-off frequency of the first-order lowpass filter was deduced. On the basis of information distortion theory analysis, a new method of digital compensation first-order lowpass filter was proposed to resolve high order filter’s realization inconvenience. The proposed method adopted first-order lowpass filter to design the CCD readout circuit. The designed first-order filter may greatly reduce the cut-off frequency and at the same time satisfy the system information distortion degree. So the designed first-order filter may be substitute for high order filter in the application system. Finally, the validity and feasibility of the method are verified by the elaborate experiment.