To investigate the effectiveness of water-soluble urea-formaldehyde gel system in enhancing the remaining oil recovery during the late-stage waterflooding development of typical fractured-vuggy carbonate reservoirs in the Tahe oilfield，a macro-visualization physical model meeting similarity criteria was designed and constructed. Based on this model，a comparative study was conducted to evaluate the plugging performance of the gel and its effect on remaining oil recovery in three types of fractured-vuggy cells. The results showed that the water-soluble urea-formaldehyde gel system exhibited good injectivity under the conditions of 150 ℃ and 252 903 mg/L salinity. In sediment-filled models，the gel mainly accumulated along cavity walls，while in collapse-filled and loose fill models，it distributed continuously and uniformly. The gel could induce flexible fluid diversion in the reservoir，and achieved effective cementation and plugging of internal reservoir media and fracture channels. Furthermore，after conventional waterflooding，injection of the water-soluble urea-formaldehyde gel system increased recovery factors by 18 . 61，18 . 13，and 13 . 64 percentage points in sediment-filled，collapse-filled and loose fill models，respectively，and maintained plugging efficiency exceeding 98 % in all three model types. This research confirmed that the water-soluble urea-formaldehyde gel system delivered excellent plugging performance and enhanced oil recovery across different fractured-vuggy structures with broad adaptability，which conld provide reliable technical support for field applications of this technology.