The present invention discloses a fiber optic connector comprises: a ferrule assembly; a spring seat provided behind the ferrule assembly; and a spring provided between the ferrule assembly and the spring seat. The spring seat has a receiving chamber having an insertion port through which a portion of the ferrule assembly is inserted into the receiving chamber; wherein the ferrule assembly is pre-assembled into the receiving chamber of the spring seat in a way that the ferrule assembly is held to be movably engaged with the spring seat. The to spring is fitted and compressed in the receiving chamber. As a result, the ferrule assembly, the spring seat and the spring are pre-assembled into an integral assembly before being inserting into a connector housing. All components of the connector except for the housing may be smoothly pulled through a small long pipe as a whole. After being pulled through the pipe, all components of the connector except for the housing may be easily and quickly inserted into the housing as a whole at one time.