A method for Bluetooth on-demand routing, and network formation, and a communication method of a Bluetooth group ad hoc network. With respect to a Bluetooth network system that has a source node, a destination node and a plurality of independent nodes, the method includes the forward and the backward path set-up steps. In the forward path set-up step, the source node sends out a route request message, thus setting up multi forward paths towards the source node and the destination node. In the backward path set-up step, the destination node in receipt of the route request message sends out a route reply message to the source node through one of the set forward paths, thus setting up a backward path. Through the set backward path, a route is formed as the most suitable path between the source node and the destination node to save battery power and provide broader bandwidth.