The invention discloses an efficient space keyword search method on a road network. Three methods including SNE, FITG and SG-Tree are put forward, wherein the performance of the SG-Tree method is the best, and the SG-Tree method is the main method of the road network space keyword search method. Specifically speaking, according to the SNE method, corresponding signatures are built for all edges of the road network, the Dijkstra algorithm is utilized, the network is traversed in a network expanding mode, and efficiency is low; according to the FITG method, a novel space index and a text inverted index are combined, the inquiring process is executed according to the pruning principle of text first and space second in serial, the efficiency is improved greatly, but defects still exist; thus, the space index and text index signature technology is utilized, a mixed index SG-Tree is put forward, corresponding signatures are built for all joints of a space index G-Tree, whether the joints comprise targets conforming to search or not can be efficiently detected, pruning can be carried out on two dimensions of space and text at the same time, and the search efficiency is greatly improved.