Abstract: This paper briefly introduces the flying spot scanner of the 789 model of Optical Character:Recognition system developed in Futan University. A method of matrix scanning with a high resolution flying spot tube is adopted in the scanner. It has the advantages of high speed and flexible control. There are also equipments of aperture correction, astigmatism correction, concentric correction, dynamic focusing, automatic brightness adjustment and so on in the scanner; so that it can scan a rather large area with high resolution, great precision, good signal/noise ratio and good stability. The system of video signal quantization includes an automatie threshold-adaptive circuit which can be adapted to the scanned documents of poor printing quality and varible darkness of characters. The signal reception system contains two channels: the red and black channels. Using the colour selection circuit with the combination of S curve transformation and time logical circuit, it ean distinguish between red and black characters. With the documents attaching to the transporting belt by pumping out the air and step-by-step document transporting mechanism, the documents of convolution type can be effectively transported. In conclusion, this scanner system is a opto-eleetronic converter with flexible control, wide range of adaptation, high resolution, great precision and high scanning speed.