The invention provides a topology construction method, system and device of a DC power distribution experiment system. The topology construction method comprises the steps of arranging at least four DC network end points; connecting the DC network end points by a side branch to form an annular DC power grid structure; arranging an internal branch in the DC power grid structure, wherein one end ofthe internal circuit is connected with the two DC network end points connected an arbitrary side branch, the other end of the internal circuit is connected with the remaining DC network end points, and two ends of the side branch and two ends of the internal branch are connected with the DC network end points via a switch module; and adjusting a topology structure of a DC power distribution network by adjusting the switch module. With the topology construction method provided by the technical scheme, various topology structures can be achieved by adjusting the switch modules.