M. S. Chen has put forward heuristics G_MC and G_MR, which are used to produce a join bushy tree with less total cost. On the basis of his work, the paper gives an improved algorithm with complexity of O(n²), by means of analysing relationship between the order of join operations and computing costs. The algorithm can reduce more total cost of a join bushy tree than G_MC and G_MR, which benefits from the following: the operation order of two arbitrary adjacent internal nodes (join operations) is optimum.