A handheld end of an endoscope, comprising a housing , an insertion end positioning assembly and a self-locking assembly , wherein the self-locking assembly is hinged to the housing ; the housing comprises an insertion port , and a protective shell ; the insertion end positioning assembly comprises a positioning member , a first positioning nut , a threaded steel tube , a through hole , a fixing member and a locking member ; the positioning member is inserted into the insertion port ; the threaded steel tube is in threaded fit with the first positioning nut ; and the first positioning nut is fixed in the positioning member ; the fixing member is fit with the through hole to abut against the threaded steel tube ; an inner bottom of the locking member is provided with a straight clamping slot , and an inner wall of the locking member is provided with an internal thread; a tail end of the positioning member is provided with a straight fixing block ; and the straight fixing block is fit with the straight clamping slot ; and the protective shell is provided outside the insertion port , and the protective shell is fixedly connected to the insertion port ; and the protective shell is provided with an external thread, and the external thread of the protective shell is fit with the internal thread of the locking member , wherein the positioning member is provided with a limiting slot ; the insertion end positioning assembly further comprises a stop piece , and the stop piece is provided in the limiting slot ; a diameter of the stop piece is greater than a diameter of the insertion port ; the fixing member comprises a second nut and a fixing screw ; the second nut is fixed to the through hole ; and the fixing screw is in threaded fit with the second nut . the housing comprises an insertion port , and a protective shell ; the insertion end positioning assembly comprises a positioning member , a first positioning nut , a threaded steel tube , a through hole , a fixing member and a locking member ; the positioning member is inserted into the insertion port ; the threaded steel tube is in threaded fit with the first positioning nut ; and the first positioning nut is fixed in the positioning member ; the fixing member is fit with the through hole to abut against the threaded steel tube ; an inner bottom of the locking member is provided with a straight clamping slot , and an inner wall of the locking member is provided with an internal thread; a tail end of the positioning member is provided with a straight fixing block ; and the straight fixing block is fit with the straight clamping slot ; and the protective shell is provided outside the insertion port , and the protective shell is fixedly connected to the insertion port ; and the protective shell is provided with an external thread, and the external thread of the protective shell is fit with the internal thread of the locking member , wherein the positioning member is provided with a limiting slot ; the insertion end positioning assembly further comprises a stop piece , and the stop piece is provided in the limiting slot ; a diameter of the stop piece is greater than a diameter of the insertion port ; the fixing member comprises a second nut and a fixing screw ; the second nut is fixed to the through hole ; and the fixing screw is in threaded fit with the second nut . <EOS>