This document provides a comprehensive study of deployment models and service models in cloud computing. It discusses the key cloud computing models including infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). It also examines the major cloud deployment models such as public cloud, private cloud, hybrid cloud, and community cloud. The document analyzes the characteristics, benefits, and limitations of each service and deployment model. It provides comparisons of the different models and concludes that cloud computing delivers scalable services but also faces challenges regarding data security, network security, and lack of user control that need to be addressed.