Service oriented architecture is more and more used in the companies, The importance of the service orientation and its advantages with the information system of the company, confront us to a new challenge. It is primarily to ensure the decision aspect of the information system of company by adopting Services Orientated Architecture like support architecture. This engineering must ensure on the one hand the flexibility of the information system and on the oth-er hand, avoids the redevelopment of the system by the decisions request. In the actual position, several obstacles force the installation of the SOA within the company. It is basically a question of the lack of method to be implemented to define the services architecture within the information system of the company which takes account the decisional aspect. Moreover, there's no existing works which treat this challenge. On the basis of these notes, we are interested, in this paper, on the develop-ment of a three-dimensional new architecture for the integration of the deci-sional aspect in SOA architectures, so that they are used perfectly. The proposal takes support, mainly, on the use of a coupling MAS-SOA. To demonstrate the application of our proposition, we use two study cases: project management and Evapo-transpiration.