The invention discloses a radiofrequency coaxial connector with a vacuum sealing function. The radiofrequency coaxial connector comprises an outer conductor and inner conductors in coaxial arrangement, each inner conductor is provided with a sealing ring in a sleeved manner, an annular sealing ring groove is arranged on an end face of the outer conductor, and sealing rings are arranged in the sealing ring groove. The radiofrequency coaxial connector is mounted on a system needing vacuum sealing and with radiofrequency input/output by adopting a threaded connection manner, pressure is generated on contact faces of polytetrafluoroethylene rings with the inner and outer conductors by the aid of threads to enable the inner conductors and the outer conductor to contact closely, and vacuum sealing of the system is realized between the outer conductor and a system cavity surface through a rubber sealing ring. The radiofrequency coaxial connector with the vacuum sealing function is simple in structure, convenient to mount, low in cost and reliable in connection. By testing, a related system applied with the connector can realize vacuum degree of 10-4Pa.