Task scheduling is an important aspect for parallel programming. In this paper, the program to be scheduled is modeled as a Directed Acyclic Graph (DAG), and the authors target parallel embedded systems of multiple processors connected by buses and switches. This paper presents improvements for list scheduling heuristics with communication contention. They use new node priorities (top level and bottom level) to sort nodes and use an advanced technique of critical child to select a processor to execute a node. Experimental results show that their method is effective to reduce the schedule length, and the performance is greatly improved in the cases of medium and high communication.