Cloud computing is a new design structure for large, distributed data centers. Cloud computing system promises to offer end user "Pay-as-you-go" model. To meet the expected quality requirements of users, cloud computing need to offer differentiated services to users. Quality of Service (QoS) differentiation is very important to satisfy different users with different QoS requirements. In this paper, various QoS based scheduling algorithm, scheduling parameters and the future scope of discussed algorithms have been studied. This paper summarizes various cloud scheduling algorithms, findings of algorithms, scheduling factors and type of scheduling and parameters considered.