Shunbei oilfield is the substitute region of Tahe oilfield which belongs to the Northwest Oilfield Branch Company, SINOPEC, it is the deepest oil and gas reservoirs in China with high formation temperature and high pressure, and there is diabase in many parts of Ordovician Sangtamu formation. Because of this, the medium-short radius horizontal well drilling in super-deep slim hole has to be used. Taking the case of well Shunbei 14H, with the difficulties of insufficient bit pressure transmit, instruments matching under high temperature and trajectory control. With the corresponding technical countermeasures, the drilling target is completed to discover oil and gas reservoir. φ120.65mm slim hole drilling is adopted for well Shunbei 14H, the completion depth is 8049.50m, creating a new record of the deepest depth of horizontal well in φ120.65mm slim hole. The completion of well Shunbei 14H provides the reference for the construction of horizontal well in super-deep slim hole.