Model reduction problem was investigated for singular systems. To solve the problem, the Silverman-Ho algorithm was given, and based on this algorithm, an optimal model reduction method for the fast subsystem was presented to obtain reduced-order stable models for singular systems. Sequentially, the H/sub /spl infin// suboptimal model reduction algorithm was obtained for singular systems. The advantage of the presented algorithm is that the impulsive nature of singular system is preserved in the reduced-order models. Then some necessary and sufficient conditions for the existence of a stable reduced-order system were given and these conditions can be verified numerically. Finally, illustrative examples were given to show the effectiveness of the proposed approach.