Abandoned farmland is the secondary succession of soil and vegetation toward the natural direction. Studying the eco-stoichiometric characteristics of carbon, nitrogen and phosphorus in riparian soil of the abandoned farmland is one of the important scientific bases for restoring and rebuilding the degraded riparian ecosystem caused by farmland disturbance. Taking the riparian farmland as the control, this paper studies the impacts of different abandonment years (2 years, 8 years, and 10 years) on soil carbon, nitrogen, phosphorus contents and their interrelationships in the riparian zone. The results showed that (1) the soil organic carbon and nitrogen content presented abandonment of 10 years > abandonment of 8 years > abandonment of farmland > abandonment of 2 years. The soil phosphorus content was in order of abandonment of 10 years > abandonment of 8 years > abandonment of 2 years > farmland. The soil carbon, nitrogen and phosphorus content of farmland and abandonment years decreased with the increase of soil depth. However, the difference of soil carbon and nitrogen was more significant than that of phosphorus. (2) The average values of C/N and C/P in riparian soils showed a trend of abandoning for 10 years, farmland, 8 years and 2 years. The mean values of N/P were as follows: abandonment for 10 years (0.78) > farmland (0.77) > abandonment for 8 years (0.77) > abandonment for 2 years (0.67), which indicated that N was the limited nutrient element for vegetation restoration in riparian zone of the study area. (3) There was a significant coupling linear relationship between C and N contents in riparian farmland and soils with different abandonment years, but the linear fitting degree between C and P, N and P was relatively low. (4) At the initial stage of abandonment succession (2 years), the soil bulk density did not change significantly, but with the increase of abandonment time (8 years and 10 years), the soil bulk density decreased significantly and soil structure improved.