A kind of software solution is provided to implement counting and division of moire fringes in this paper. No complex electronic circuit of digital counter exists in the digital reader that adopts this software solution. The counting and division of the fringes are completed in DSP (digital signal processor), so it can solve the problems that counting circuit can't match the subdivision system properly by logical judgement. Because of utilizing high-speed optoelectronic convertor and flash sample technique, the system can process moire signal with wide frequency range. The example demonstrated in the paper can count and divide signals from DC to 1MHz, i.e., if the optical sensitivity of the signal is 1 fringe per micrometers , the fastest measure speed can reach 1000mm/s. The experimental result shows that the software solution has high accuracy and sound reliability.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.