Abstract: Based on having analyzed the working principle and the control interface circuits of the laser-typersetter, this paper described methods for the graphical data storage and the representation, and methods for a bitmap segmenting and output. By using these methods, problems such as speed dismatch between a computer and a laser-typersetter, contrariness between small memory and large amount of graphical dada were solved. Therefore, we can read data from files continuously and deliver data by segmenting. As a result, images can be printed in the laser-typersetter without lossing fidelity.