The DWTSG concept is proposed as a advanced steam generator of liquid metal reactor to avoid sodium-water reaction incidents in the SG. The optimization of steam generator from economic viewpoint is to minimize the total cost of heat transfer area and pumping power. The baffles are primarily used in shell and tube steam generator for inducing cross flow over tube bundles, and as a results, improving heat transfer performance. In this paper a computer based design method, which covers segmentally baffled steam generator is developed for preliminary DWTSG design. And parametric sensitivity studies are done to determine required heat transfer area to meet the specified heat capacity by calculating minimum or allowable shell-side pressure loss.