Abstract: - Cloud computing is a prominent technology nowadays. Companies like Amazon, Google and Microsoft are enhancing the services provided for their users. Security issue is a problem that matches users to the cloud systems. Secured network access is an example of flexible, flexible cloud computing of configurable computing resources. Cloud computing released using client computing, service providers, or low management efforts. Such as the Cloud Service Provider (CSP) service is fully organized, end users don’t want to see the information of a particular technology. In this paper, we studied about various service models deployed in the cloud network such as IaaS, PaaS and SaaS. There are many problems that are faced in cloud computing are described in this paper and it is wireless network so it has many security issues also which are also studied.Keywords: Cloud Computing, CSP, IaaS, PaaS, Saa, Security and Privacy.