Abstract: Simulation of formation damage is an active field in software development in petroleum industry. At present, most programer use function decomposition or data flow approach to develop their software, but there are many limitation in those two methods: they make problems complex, bad communication between programer and geologist and few recycle of the software. So, a new method was suggested in the paper, i.e. object-oriented software development for simulation of formation damage. The geological reality was expressed by objeet. The property and law of geological reality are object's attribute and service, and interaction of objects can be implemented by message connection, thus, they form an organic unit.