Abstract: Aiming at the current situation of manual stenciling for steel pipe identification，an automatic stenciling control system for steel pipe-end marking is designed. The system uses a light curtain sensor to detect the position signal of the robot arm，and brings about the safe interlock between the space position of the robot arm and the position of the pipe end through the targeting sensor. According to the process flow，when the steel pipe is running on the conveying roller table，the robot algorism can automatically stencil the mark upon the pipe end after the roller table is stationary as per the logic judgement via. program algorism. The system is suitable for the automatic operation of mark-stenciling for steel pipes with a size range of Φ406~1 620 mm. The actual production practice shows that thanks the on-line operation of the said system，the stenciling efficiency is enhanced by 29%，while the working environment is improved，and the fully automatic unmanned operation is realized.