Design of system architecture is important problem that must be solved in each software development process. Success of software exploitation depends on selected architecture. Usually there is more than one requirement for software architecture that must be solved to reach the expected result. To make architecture selection before the software is developed, architecture must be modelled. E-service system architecture stands up from many components. Very important element of e-service system architecture is orchestration of particular e-service that contains WEB services and mutual relations. To design architecture such of e-service system, first full a e-service algorithm must be described as oriented graph where vertexes of the graph in point of fact are executable activities of e-service algorithm and the edges in graph means that in the execution of the algorithm graph after activity in the one of the vertexes follows activity in the next vertex. Initially assume that e-service algorithm graph is WEB service graph future design of e-service can be made by transformation of the WEB service graph. The vertexes in WEB service graph are WEB services and edges in WEB services graph means that WEB services are mutually related and direction of the edge shows that after WEB service execution in one vertex follows next WEB service execution in next vertex. By mutual segmentation of WEB service graph vertexes in all possible combinations all possible WEB service graphs are calculated that describes the architecture of e-service system. The all WEB service graph segments are calculated by recursive algorithm. If a large e-service algorithm graph must be processed with more than twenty vertexes the initial design and analysis must be performed to put restrictions on WEB service graph segmentation that restricts to join defined vertexes in one segment or e-service algorithm graph must be partitioned in several equal partitions with minimal cross partition edges and each algorithm graph partition can be transformed to WEB service graph and solved as a separated task of design. After detecting all possible WEB service graph vertexes combination segments, architecture selection can be performed by selecting e-service system architecture from set of segmented WEB service graphs. Selection of e-service architecture instance can be performed as multi-criteria optimisation task in evaluated set of WEB service graphs. Examination of all possible solutions of system architecture exclude probability that local maximum can be selected.