Porous HAp/chitosan-alginate composite scaffolds were successfully synthesized by insitu co-precipitation method. During the preparation of HAp/chitosan-alginate composite scaffolds, the interaction between chitosan-alginate molecules would be reduced with increasing HAp content, with the resulting that the chitosan-alginate molecules were homogeneously dispersed in the composite scaffolds. The chitosan-alginate content was found to be almost consistent as initially added during the preparation. These results imply that chitosan-alginate was almost perfectly incorporated into the composites. It was found that the pore structure of the composite scaffolds with low HAp content was similar to chitosan-alginate scaffolds, and the morphology of uniform microstructure was unaffected by the presence of HAp. However, the pore diameter decreased with increasing the HAp content up to HAp content of 30 wt%, eventually the pore structure was collapsed and the composites scaffolds appeared to be agglomerated at higher HAp content.