The invention discloses an online guide pipe connector assembly stress detection system and a detection and identification method. The system comprises a system setting module used for setting the model of a guide pipe, setting the installation position of the guide pipe and setting data acquisition parameters; a data acquisition module used for obtaining and storing impact response data through carrying out modal testing by utilizing the hammering method; a modal analysis module used for obtaining a standard frequency response function of the guide pipe, and the dynamic stiffness of the guidepipe structure; a sample data setting module used for establishing a standard frequency spectrum database for the assembly of the guide pipe, and carrying out the frequency spectrum display of the frequency response function; and an assembly stress identification module used for judging the assembly of the target guide pipe is qualified or not. The system and the method can be applied to the installation stress detection during the assembly process of a pipe , and can also be applied to the detection on the change of the installation state of a connector during the use process of the pipe.