This paper presents simulation results of pitting defects with furan casting technology using Procast simulation software. Based on the initial conditions (such as actual product requirements, drawings ...), the author develops a preliminary production plan later through simulating the casting process on procast software to determine the method. The article has been established, building pouring system as well as conducting modeling simulation of casting process. The research results show that after calculating simulation with Procast dedicated software, the concave defects location has been identified. Since then the author has issued warnings about the occurrence of defects in castings; determine the exact location of these defects. From the simulation results, the author has applied to the actual production and found that the simulation of procast software casting process is really accurate in making the defects of castings.