Resource management plays an important role in cloud computing

while scheduling is one of the key techniques in resource management

which has a direct influence on cloud computing.However

due to the heterogeneous and dynamic features in cloud computing

cloud scheduling is complicated and difficult.This paper uses five factors to describe general scheduling problems

and gives examples of different types for each factor.We analyze the traditional scheduling algorithms in parallel and distributed environment

and the current research in cloud computing.And we give the trend for cloud scheduling under its difficulties and challenge.Our work indicates the directions and ideas for future research in cloud scheduling.