In this study, a new framework for the computational fluid dynamics (CFD) using the object-oriented programming language C++ is developed. The CFD method is pressure implicit with splitting of operator (PISO) algorithm. It is the finite volume method (FVM), and can be used to solve the transient incompressible fluid dynamics. The largest feature of this study, the overall framework design is combined with basic concepts of the FVM and the PISO method. The framework is divided into the flow field (Field) class, the pressure control volume (Pressure-control volume) class and the velocity control volume (velocity-control volume) class, respectively. In addition, the velocity control volume class can be divided into the u-control volume class, the v-control volume class and the w-control volume class, respectively. In order to describe the class contents and relationships, the unified modeling language (UML) is adopted. According to the numerical results of the heat flow analysis, it can prove that the framework is the effective and accurate for the analysis of the transient incompressible fluid dynamic responses.