Abstract: Analyzed in the paper are the technological difficulties associated with the horizontal centrifugal casting process and heat treatment process for the small-sized martensitic pipe.Also described are the details and achievement of the R& D of the said pipe.The analysis results in the following conclusion.Addressing the problem that since the cast piece is apt to produce gas hole, and improper heat treatment is apt to occurrence of defects like micro-cracks, so actions as follows should be taken to ensure the small-sized CA-6NM martensitic stainless pipe to be free of any defect, and possess fine metallographic structure and mechanical properties.After the casting mould is sprayed with the coating, immediately blowing off the water vapor in the inner cavity with compressed air or argon;appropriately raising both the mould temperature and the casting temperature;getting the pipe cooled down to about 260℃ via oil-quenching, and then getting it out of the oil, and then having it air-cooled down to about 100℃, and immediately tempering of it.