This paper presents a method for analyzing Web Service-based dynamic business process, using a business process slicing method to capture the asset (service or information) derivation pattern, allowing to maintain providers’ policies during the full lifecycle of assets in a collaborative context. Firstly, we propose a Service Call Graph (SCG) model, extending the System Dependency Graph, to describe dependencies among partners in a business process. Analysis can be done based on SCG to group partners into sub-contexts. Secondly, for analyzing SCG, we propose two slicing strategies, namely ’asset-based’ and ’request-based’ slicing, to deal with the scenarios of both pre-processing business process scripts and on-the-fly analyzing service compositions. Security analysis can be achieved focusing on each sub-context, by examining downstream consumers’ security profiles with upstream asset providers’ policies.