Abstract: Programmability of parallel programs is one of the difficulties of parallel computing In this paper, a method of parallel programming is proposed, which uses design patterns in program refinement calculus In this method, the Schema calculus of Z notation is expanded with parallel concepts and representations The knowledge of problem solving and parallel development is defined and described using design patterns With the expanded Schema calculus, design patterns can be composed with model specifications and refined step by step to get abstract parallel program This method is specified in details through examples