Abstract: Based on the ANSYS finite element model, this paper studies the externaltendon and the key technologies of the external prestressedreinforcement. The conclusions are as follows. To a rationalfunction position of the external tendon, the original structure'sstress condition must be complied as far as possible to ensure thesafety performance of thereinforcement. The reinforcement tendon should use the replacementprinciple of equivalent area, for the reasonable constructionprocess. The strength tendon's junction device must keep the principleof ``conformation, thin, strong''. The engineering disposal oflongitudinally and staggered layout for the external tendon in reinforcementengineering, which will promote the integral structure ductility.