Fire-induced effects on biota activity and diversity, and soil attributes, could have implications for biodiversity conservation and recovery of semiarid grassland ecosystems. Here, we examined the abundance and diversity of ground-dwelling arthropods, and soil attributes in burned and unburned grasslands in the semiarid Nanhuashan Natural Reserve in western Loess Plateau of China. Arthropods and soil were sampled in springtime one year after fire disturbance. We found no significant differences in total abundance of ground-dwelling arthropods between burned and unburned grasslands. However, the taxonomic richness and the Shannon index of ground-dwelling arthropods were found to be significantly greater in burned than unburned grasslands. Postfire effects also indicated significant differences in dominance hierarchy among taxa within functional groups as a consequence of increasing predatory abundance but decreasing phytophagous one from unburned to burned grasslands. Likewise, soil bulk density declined, whereas soil C/N increased significantly from unburned to burned grasslands. In conclusion, fire could promote the taxonomic richness and the diversity of ground-dwelling arthropods, thus being indicators of positive effect of fire disturbance on biodiversity conservation of semiarid grassland ecosystems of northwestern China. However, soil bulk density and soil C/N could be susceptible to fire-driven changes of soil attributes.