Abstract: In order to study the topological structure of vessel network, and to make up the undesirable gaps produced by segmenting, and to connect broken vessels for the integrity of vascular structure, a projecting and curve fitting method is proposed. Based on the skeleton of the segmented network, vessel branches are projected onto the XY and XZ planes; then nonlinear curve fitting algorithms are applied for connecting discontinuities of broken branches, sum of the squared errors and R-square are used for determining fitting effects; the original curves are fitted by back projection, and the broken vessels are finally connected. Meanwhile, a picking strategy for preserving appropriate key points of vessel data is put forward through comparison of different fitting methods. Experimental results show that the method performs well compared with existing connection methods.