The utility model discloses a catheter positioning system when pile foundation underwater concrete pours has following advantage: catheter positioning system when pile foundation underwater concrete pours, through welding position on pipe ring, the holding ring adopts phi 28mm's HPB400 screw thread location muscle and phi 28mm's beaded finish welding constitution. A islam ghusl distance is 300mm between HPB400 screw thread location muscle and the steel reinforcement cage inner wall of catheter positioning system when pile foundation underwater concrete pours, phi 28mm. The utility model discloses an improve welding position system on the pipe to solve the pipe and transferred and promote the orientation problem of in -process. This patent is improved through above -mentioned, has solved pipe off normal problem, has prevented the concrete quality problem because of the off normal produces.