Abstract: Master-slave teleoperated arc welding demands high accurate trajectory and sufficient weldingspeed,And during the operation the welding gun is not intouch with the welded workpiece,hence the visiuaIdepth message of monitor system is much more important to operation accuracy and efficiency. According tothe monitoring behaviour in arc welding process,an eye-in-hand helmeted stereo TV monitor system hasbeen built. aiid itsoptiral principal is explained in defail. Experimental results prove that the visual depth ac-curacy of this monitor svstem is about ±1mm. As contrasted with the two dimention TV monitor svstem,thestereo TV monitor system not only reduces the seam track deviation obviously, but also rnakes the trends ofseam track deviation gentle as the welding speed increases.