Top-down control from predators on herbivores provides an effective and economic means of control in the agricultural landscape. Research into which factor, in areas at different scales, has the strongest effect on spider diversity is beneficial to facilitate increasing the diversity of spiders. In most regions, spider diversity shows a declining trend, the reasons behind which are not fully explained by available data. As a result, many researchers have focused on the protection of the biodiversity, however, in our study area, the agro-landscape along the lower reaches of the Yellow River, the current level of protection is inadequate. We therefore set samples in the woodland habitat in our study area and, by comparing the effect of different factors (landscape and environment variables) on the spider diversity in different scales (100, 200, 350, 500 m), we tried to identify which factor in which scale had the most important effect on the spider diversity in the study area. Spider abundance was selected because of its strong correlation (P < 0.05) with the number of species and then data (i.e. the number of specimens that caught) were ln transformed. In order to compare and rank the factors, we selected the lowest Akaike Information Criteria values using the step AIC function within the MASS package in the R program. Owing to the small sample sizes, we used AICc instead of AIC, and to measure the influence of each variable in every model, we also calculation the Akaike Weights (W_i). To characterize the species of spider in relation to the three groups of herb coverage, an indicator species analysis was undertaken using the IndVal function in the Labdsv package in R. The results showed that the dominant spider species in the study area were Pardosa astrigena, Hitobia unifascigera, Pirata piratoides and Drassyllus shaanxiensis. A different effect existed between factors and spider diversity in different scales, but the best scale to study factor effect on spider diversity was 100 m. In spring, the most important factor influencing spider diversity was herb coverage, followed by crop area, woodland area and distance from road. In summer, only herb coverage and herb height had an obvious influence. Through IndVal value analysis, we found that different species of spider had different tendencies to herb coverage, but the most of the spider species preferred high herb overage, especially the spiders in Lycosidae family. However, a few spider species, such as Xysticus hedini Schenkel, Evarcha albaria, Achaearanea asiatica and Araneae, were more frequently appear in woodland with Medium or Low herb coverage. According to the indicator species analysis, some spider species also had a relatively high indicator value (>0.2), which was associated with High herb coverage. Examples of such species are Pardosa astrigena, Hitobia unifascigera. This study demonstrates that herb is the most important of the factors tested with respect to spider diversity. Therefore, increasing herb cover in the agricultural landscape would contribute to an increase in the number of predatory arthropod and improve the abundance of predatory arthropod conducive to the protection of biodiversity in the agricultural landscape and the controlling of biological pests in the terrestrial ecosystem.