Taking the drilling cores of the 10th rhythmite of Eq34 Submember(Eq34-10 rhythmite) and 5th rhythmite of middle Eq40 Submember(Eq40-5 rhythmite) of Qianjiang Formation in Wangchang anticline as main research object, the provenance properties and sedimentary environment of different rhythmite in Qianjiang Depression were studied through the analysing of XRD and ICP-MS. The results show that there are obvious differences in mineral composition, REE content and distribution between the two rhythmites. Clay minerals and quartz are the main silicate minerals in Eq34-10 rhythms, while plagioclase, clay minerals and quartz are the main silicate minerals in Eq40-5 rhythmite. The contents of REE and silicate minerals of the two sets were positively correlated. The REE fractionation degree of clastic rock in Eq34-10 rhythmite is higher than that of carbonate rocks, while that of clastic rock in Eq40-5 rhythmite is similar to that of carbonate rocks. It is indicated that the provenance of these two rhythmites is different, or the climate is relatively warmer, humid and wind erosion is stronger in the depositional period of Eq34-10 rhythmite. The sedimentary water of these two sets of strata are in reductive environment, and the lake water may be deeper during the deposition period of Eq34-10 rhythmite, which is more conducive to the accumulation and preservation of organic matter. Therefore, it is inferred that Eq34-10 rhythmite has more exploration potential.