Paleo-sedimentary environment could be recovered qualitatively or semi-quantitatively by using elements or element ratios sensitive to sedimentary environment of mudstone. In this study, major, trace and rare earth elements compositions, XRD and SEM of 12 rock samples from Xujiahe Formation were analyzed to investigate the paleoclimate, paleo-sedimentation and paleo-provenance in the Qilixia section, northeast Sichuan area. The results show that the content of clay minerals in the fine-grain samples of the Xujiahe Formation in the Qilixia section is dominated by illite-montmorillonite mixed-layer mineral (62%~88%), followed by chlorite (3%~19%), illite (3%~11%), and kaolinite (1%~9%), with FeO/MnO ratios being 28.08~104.23, reflecting the warm and humid climatic conditions of the Late Triassic in the Qilixia area, in which the climate of the 3^rd and 5^th members of the sedimentary period were relatively warm and humid, and the climate of the 1^st, 2^nd and 4^th members of the sedimentary period were slightly arid and hot; lower Li, Sr, Ni and Ga abundances and Sr/Ba ratios (0.08~0.24) of the Xujiahe Formation suggest that the paleo-salinity of sedimentary water was low; V/(V+Ni) ratios (0.69~0.85) and Ce_anom(0.26~0.30) indicate that there existed a reducing environment in Xujiahe sedimentary period, with the reductivity of water gradually weakened from the 1^st to the 5^th member of the Xujiahe Formation. The REE distribution patterns of samples in the study area are similar to those in South Qinling Mountain, Longmen Mountain and Micang-Daba Mountain areas, indicating that the early provenance in this area was derived mainly from the mixture of diorite, granite and basalt in the South Qinling Mountain, with some from the granite of Longmen Mountain, whereas the late provenance was mainly derived from the granite of Micang-Daba Mountain.