An optical fiber connector for inserting into an optical fiber adapter, the optical fiber connector comprising: a fiber ferrule having at least one guide pin hole for receiving a guide pin to align the fiber ferrule with a mating fiber ferrule, the guide pin hole defining an axis; a coil spring having a front end, a rear end and a middle section between the front end and the rear end, the coil spring further having a first opening formed within the front end; a spring seat having opposing front and rear surfaces (41, 42), the front surface being in contact with the fiber ferrule, wherein a second opening is formed within the rear surface, the second opening has two opposing first sides and two opposing second sides, the first sides connect with the second sides, and a spring push positioned to push the coil spring toward the spring seat, the spring seat further comprising: two first tooth portions extending from the rear surface into the first opening of the coil spring, the first tooth portions being respectively positioned by the first sides of the second opening, wherein the first tooth portion has a top and a bottom fixed on the rear surface, the first tooth portion further has a first inner side surface and a first outer side surface opposed to the first inner side surface, the two first inner side surfaces are positioned to face each other, wherein the optical fiber connector is characterized in that: the first outer side surface of the first tooth portion is inclined and a position at the first outer side surface defines a first inclination angle with respect to the rear surface of the spring seat, the first inclination angle gradually decreases from the bottom toward the top of the first tooth portion, the two first outer side surfaces are curved and shaped in such a manner that inner edges of the first opening at the front end of the coil spring are able to slide thereon and the coil spring is still able to apply a biasing force to the spring seat in the axial direction when the coil spring buckles, and wherein the two first outer side surfaces are further shaped to prevent the coil spring from making direct contact with the rear surface of the spring seat. a fiber ferrule having at least one guide pin hole for receiving a guide pin to align the fiber ferrule with a mating fiber ferrule, the guide pin hole defining an axis; a coil spring having a front end, a rear end and a middle section between the front end and the rear end, the coil spring further having a first opening formed within the front end; a spring seat having opposing front and rear surfaces (41, 42), the front surface being in contact with the fiber ferrule, wherein a second opening is formed within the rear surface, the second opening has two opposing first sides and two opposing second sides, the first sides connect with the second sides, and a spring push positioned to push the coil spring toward the spring seat, the spring seat further comprising: two first tooth portions extending from the rear surface into the first opening of the coil spring, the first tooth portions being respectively positioned by the first sides of the second opening, wherein the first tooth portion has a top and a bottom fixed on the rear surface, the first tooth portion further has a first inner side surface and a first outer side surface opposed to the first inner side surface, the two first inner side surfaces are positioned to face each other, wherein the optical fiber connector is characterized in that: the first outer side surface of the first tooth portion is inclined and a position at the first outer side surface defines a first inclination angle with respect to the rear surface of the spring seat, the first inclination angle gradually decreases from the bottom toward the top of the first tooth portion, the two first outer side surfaces are curved and shaped in such a manner that inner edges of the first opening at the front end of the coil spring are able to slide thereon and the coil spring is still able to apply a biasing force to the spring seat in the axial direction when the coil spring buckles, and wherein the two first outer side surfaces are further shaped to prevent the coil spring from making direct contact with the rear surface of the spring seat. two first tooth portions extending from the rear surface into the first opening of the coil spring, the first tooth portions being respectively positioned by the first sides of the second opening, wherein the first tooth portion has a top and a bottom fixed on the rear surface, the first tooth portion further has a first inner side surface and a first outer side surface opposed to the first inner side surface, the two first inner side surfaces are positioned to face each other, wherein the optical fiber connector is characterized in that: the first outer side surface of the first tooth portion is inclined and a position at the first outer side surface defines a first inclination angle with respect to the rear surface of the spring seat, the first inclination angle gradually decreases from the bottom toward the top of the first tooth portion, the two first outer side surfaces are curved and shaped in such a manner that inner edges of the first opening at the front end of the coil spring are able to slide thereon and the coil spring is still able to apply a biasing force to the spring seat in the axial direction when the coil spring buckles, and wherein the two first outer side surfaces are further shaped to prevent the coil spring from making direct contact with the rear surface of the spring seat.