The rock-soil interface of weathering profiles derived from carbonate rocks is generally sharp in the field, and this is an obstacle for exploring weathering mechanism of carbonate rocks by directly studying the development characteristics of field geological cross-sections. This paper selected the rock-soil interface of four typical in-situ weathering profiles of carbonate rocks as the subject investigated in central Guizhou Province and western Hunan Province, China. By simulating field well-drained weathering condition in hot season, water saturated with CO2 was percolated through sample columns filled with rock powder at rock-soil interface of studied profiles, the temperature was among 24～29.5℃ throughout the leaching cycle, and the leaching end was marked by complete dissolution of carbonate. Through dynamic analyses on major rock-forming elements of leachate and leaching residue, weathering mechanism of rock-soil interface of weathering profiles of carbonate rocks was preliminary revealed. The research result is as follows: ① During weathering of carbonate rocks, dissolution of carbonate is synchronous with decomposition of acid-insoluble material, and acid-insoluble fraction has shown a clear weathering tendency at the begin of carbonate dissolution. ② In well-drained weathering environment, base cations and Si stemming from decomposition of acid-insoluble residue including silicate are more inclined to the migration along with leaching solution, which makes it difficult for authigenic clay minerals such as smectite, illite, kaolinite, etc., to form during weathering. ③ During water-rock interaction on rock powder layer of weathering profiles of carbonate rocks, when carbonate volume for water-rock interaction is excessive, dissolution intensity of carbonate is mainly constrained by the texture of rock powder layer. the grain size is the more coarse, the penetrability is the higher, the water-rock interaction time is the shorter, carbonate dissolution volume is the lower, and vice versa. However, acid-insoluble fraction for water-rock interaction is inadequate throughout the leaching cycle, and its volume is main factor restricting water-rock interaction intensity. ④ In subaerial environment, Ti, Al, and Fe are inert elements, Mn and P show significant activity.