This paper presents some observations on Dependency Analysis of Service Oriented Architecture (SOA) based systems. In general, dependency analysis is based on the internal properties of artifacts (objects/components/services) and inter-relationship between the artifacts in the system. In order to make a dependency analysis for SOA based systems, one have to consider the special features of SOA that make them different with other approaches. This paper surveys the previous works taken on dependency analysis of service oriented systems. The present work provides insights about definitions related to service dependency, the modeling and analysis techniques of service dependency analysis, failure results to service dependence and some research challenges of the topic.The contribution of this paper is for novice researchers working on this topic as they can get an overview of dependency analysis of SOA based systems for their further research.