The invention relates to a speed regulating method for a transvaginal color ultrasound probe cleaning device applicable to gynaecology and obstetrics. The adopted transvaginal color ultrasound probe cleaning device applicable to gynaecology and obstetrics comprises a handheld shell, a speed regulating device, a transmission device, a distance regulating device and an output device; the speed regulating method comprises the following steps that a speed regulating screw is rotated, and the speed regulating screw can only rotate instead of vertical motion due to the effect of a limiting insertionblock; the speed regulating screw acts on a thread insertion block and then drives a sliding lantern ring to move up and down; the contact position between an input rotating wheel and the sliding lantern ring is changed, and the input rotating wheel is used for driving the effective transmission radius of the sliding lantern ring to change; the transmission ratio of the input rotating wheel to the sliding lantern ring is changed, so that the rotating speed of a cleaning brush is changed, and the cleaning effect of a transvaginal color ultrasound probe is regulated.