A subdividing method for non-orthogonal grating moiré signals is studied, and a circuit scheme of the non-orthogonal grating moiré signal digital subdividing system is proposed based on signal sampling, pre-processing, and subdivision structure to complete 32~512 times signal subdivision on the FPGA platform. Analysis is made of signal amplitude ratio and sampling rate,and two factors in the circuitry. A model of signal amplitude deviance is constructed, and the quantitative relation is established between signal amplitude ratio k and subdivision value N. Test results suggest that required compensation for signal amplitude deviance be-comes higher steadily when the subdivision value N grows. A model of signal frequency/sampling frequency is constructed, and the quantitative relation is established between the quotient of signal frequency and sampling frequency f/fs and subdivision value N. Test results suggest that required sampling frequency becomes lower steadily when the subdivision value N grows.