The route planning engine has already become an important part for an online map system. The route planning algorithm is the key for the engine. The existing improvements for A* algorithm are mainly on the preprocessing part in which the roadmap data were layered statically. In this paper, an adaptive hierarchical method was proposed with an improved heuristic function which has goal-direction process. It greatly improves the efficiency and usability of A* algorithm in the engineering road planning system. The experiment result shows that the algorithm takes up only 42% of the search space and 13% of the search time when compared with the general A* algorithm.