In this research the dynamic impact of the interconnection on the rotor angle Stability for Synchronous Generators in the Syrian Network were analyzed through the dynamic simulation of the power system and building of equations is linear and then use the program PSS / E (Power system simulation)to resolve and identify determinants of the system and determine critical fault clearing times of three-phase faults on the 400 KV addition to identifying the angular revolving generators and thus to verify the stability whether of its work independently within the Syrian electrical system or as part of the five countries interconnection project.