Abstract: In order to explore the effects of different planting methods on the physical and chemical properties of paddy soil and the economic benefits of rice-crab co-culture system, a continuous positioning monitoring system for 13 years, with the treatments of rice-crab cultivation (CR) and single rice field (FP), built in the central area of Liaohe River Delta, was applied to investigate the basic physical, chemical and biological properties of soil as well as the yields and benefits of rice and crab. Compared with FP, the soil physical and chemical properties of CR were significantly improved, especially in the first 3-4 years. In the following 10 years, the changes of them were small, reaching a relatively stable state. Generally, soil bulk density decreased by 0.05 g cm⁻³ and soil porosity increased by 2.1%. Soil organic matter increased from 25.5 g kg⁻¹ to 28.4 g kg⁻¹, increasing by 2.90 g kg⁻¹. Total nitrogen increased by 0.19 g kg⁻¹. Moreover, the available nitrogen, phosphorus and potassium increased by 21.2 mg kg⁻¹, 2.23 mg kg⁻¹ and 29.0 mg kg⁻¹, respectively. Soil microbial biomass carbon increased by 128%. In terms of nitrogen use efficiency (NUE), NUE of CR treatment was significantly increased by 10.3% higher than that of FP treatment. From the economic benefits of rice and river crab, there was no significant difference in rice yield, but the rice price increased by 13.8% due to the optimization of rice quality. Combined with the output of river crab, the net economic benefits per hectare increased by 18269 yuan, realizing the goal of double harvest of rice and crab. In conclusion, the rice-crab co-culture mode not only improved the soil properties and NUE, but also ensured rice yield and economic benefits of river crab, which was the best ecological planting and breeding model with both economic and ecological benefits.