Rice-crab co-culture (RC) is a comprehensive cultivation model that combines rice production and aquaculture effectively by using the theories of interspecific mutualism, food chain and ecological niche, which is of great significance to promote the development of agricultural ecology. Since spiders are important predatory natural enemies in rice fields, in order to find out the ecological niche characteristics of major spiders in the rice-crab co-culture system, this study investigated the species and quantity of major spiders in the conventional rice fields and rice-crab co-culture rice fields of time and space, and systematically analyzed the ecological niche width and overlapping characteristics of spiders by using the ecological niche theory analysis method. The results showed that: (1) A total of 892 spiders belonging to 30 species of 10 families were investigated in the two rice fields. The proportion of spiders in RC fields was 57.96%, 15.92% more than that in conventional rice fields. The number of Lycosidae, Linyphiidae, and Tetragnathidae in the two treated fields ranked first, and the number of Lycosidae was the highest, with 18.60±1.17 (the conventional rice fields) and 26.00±2.39 (the rice-crab co-culture rice fields), respectively. (2) In the temporal dimension, the niche width of Lycosidae, Linyphiidae and Salticidae increased, while that of Tetragnathidae decreased in rice-crab co-culture system. In spatial dimension, the niche width of Lycosidae, Linyphiidae and Tetragnathidae increased, while those of Clubionidae decreased in rice-crab co-culture system. From the perspective of temporal-spatial dimensions, the niche width of Lycosidae and Linyphiidae increased significantly by 49.64% and 47.49%, respectively, while that of Clubionidae decreased by 25.04%.(3) The temporal-spatial niche overlap index and niche proportional similarity index of most spiders increased or remained the same in rice-crab co-culture system, however, the index of Clubionidae to Araneidae and Clubionidae to Tetragnathidae decreased. In this study, the characteristics of the ecological niche of main spiders in the rice-crab co-culture system were analyzed for the first time. Rice-crab co-cropping changed the temporal and spatial ecological niche, overlap and similarity characteristics of spiders to varying degrees by affecting the activity intensity, distribution pattern and quantity structure of spiders in paddy field environment. When the competition intensifies, the spiders will increase the degree of utilization on more resource sequences, so as to better exert the ability of insect controlling.Rice-crab co-culture not only increased the number of spiders, but also changed the degree of spiders' utilization of temporal and spatial resources, resulting in a higher level of resource utilization, a more even distribution, and a longer period of occurrence, and facilitating spiders to perform their pest control role better. This study provides basic data for the study of spider ecological niche in rice-crab fields.