Abstract: Accurate constraints on coseismic surface displacement are critical for understanding earthquake rupture processes, assessing regional seismic hazards, and characterizing surface deformation partitioning. Compared with conventional near-fault measurements, long artificial linear markers crossing rupture zones can capture permanent deformation over larger apertures and thus provide additional constraints on total coseismic displacement and distributed off-fault deformation(OFD). The 8 January 2022 Menyuan Mw6.6 earthquake on the Haiyuan fault zone, northeastern Tibetan Plateau, produced a clear surface rupture and preserved multiple pasture fences crossing the fault, providing an excellent opportunity for such analysis. Using UAV imagery, we generated 2~6 cm resolution digital orthophotos and DEMs covering the entire rupture zone, and combined them with field investigations to map the surface rupture in detail. We further conducted multi-aperture displacement measurements on 12 groups of long fences crossing the rupture zone.The coseismic surface rupture is ~28 km long and consists of a southern branch along the Tuolaishan Fault and a northern branch along the Lenglongling Fault. Based on geometric characteristics, the rupture can be divided from west to east into four segments (S1~S4). Surface ruptures are mainly expressed as NE-striking right-stepping en echelon transtensional cracks and obliquely arranged compressional mole tracks. Rupture-zone width varies significantly along strike, reaching a maximum of ~160 m, but is generally 10~30 m except in the wider S3 segment. Measurements from cross-fault fences show that displacement within the visible rupture zone ranges from 0 to 2.8 m, whereas total coseismic displacement ranges from 1.2~4.1 m, indicating an OFD ratio of 27%~76%. The maximum total displacement (4.1±0.8 m) occurs in the Lenglongling S3 segment near the epicenter, where the mean OFD ratio is ~33%. Westward from S3, total displacement decreases gradually, while the proportion of OFD generally increases; in the Tuolaishan S1 segment, the mean total displacement is 1.7±0.5 m and the mean OFD ratio reaches 55%. Compared with previous near-field measurements, the larger displacement values obtained here likely reflect the broader measurement aperture, which captures more complete coseismic deformation. These results emphasize the importance of incorporating OFD in evaluating total earthquake displacement and seismic hazard.