Service composition has been recognized as a flexible way for resource sharing and application integration. Quality of service (QoS) is an important issue for composite services. In this paper, we address the issue of component services selection to ensures their composition satisfy given QoS constraints. We propose the concept of reduction tree as a general scheme to aggregate multi-dimensional quality. And then a heuristic algorithm MCSC_HEU is presented to find execution plans satisfying multiple QoS constrains, with the main idea of evaluating partial plans by a heuristic function during the course of reduction. The time complexity of MCSC_HEU is of polynomial level. Extensive evaluations show that MCSC_HEU succeeds in finding feasible plans with very high probability but demands much less time than exhausting search. So it is an efficient solution for QoS aware service selection with multiple constrains.