Abstract: In order to realize rational well group division on tree-type oil & gas gathering and transportation pipeline networks, the tree-type structure of multi-well concatenation is included in the well group division. In this paper, a mathematical model for well group division was established by taking the shortest distance sum between wells and stations connected in the tree-type pattern as the object function and the affiliation of wells and stations as the optimization variable. And this model was solved by means of the hybrid algorithm which combines the genetic algorithm with the Prim algorithm. Firstly, all well sites are searched by using genetic algorithm to acquire the initial affiliation of wells and stations. Then the shortest distance sum between wells and stations is calculated by using the Prim algorithm, and the optimal solution is obtained based on iterative process of genetic algorithm. In the case application, well group division scheme and station coordinates of tree-type pipeline network are worked out, and the sketch of tree-type connection between wells and stations is plotted. Compared with the stellated pipeline network, the tree-type pipeline network is shorter in total pipeline length, lower in investment cost and higher in economic benefit.