We examined the seasonal distribution of the functional groups of ground-active arthropods by pitfall traps in Lycium. barbarum plantations in oasis of Ningxia in spring, summer and autumn of 2018. The relationship between the abundance and richness of functional groups and environmental factors was also examined. The results showed that: (1) the functional groups of ground-active arthropods in L. barbarum plantations included phytophagous, predatory, saprophagous, and omnivorous animals, accounting for 6.31%, 86.75%, 2.01% and 4.86%, respectively. It suggested that the predatory animals dominated the ground-active arthropod communities. (2) The abundance and biomass of phytophagous arthropods were significantly higher in spring than in autumn, with the intermediate values observed in summer; the richness of phytophagous arthropods was significantly higher in summer than in autumn, with the intermediate values observed in spring. The biomass of predatory arthropods was significantly higher in summer and autumn than in spring; whereas there was no significantly different in the abundance and richness of predatory arthropods between the three seasons. Likewise, there was no significant difference in the abundance, biomass and richness of saprophagous arthropods between different seasons. Nevertheless, the abundance and richness of omnivorous arthropods was significantly higher in spring than in summer, with the intermediate values observed in autumn; whereas there was no significant difference in the biomass of omnivorous arthropods between different seasons. (3) There was positive correlation between the abundance of predatory arthropods and soil moisture; there was positive correlation between the abundance of saprophagous arthropods and soil total phosphorus, and there was positive correlation between the abundance of omnivorous arthropods and soil total nitrogen. However, there was negative correlation between the abundance of phytophagous arthropods and soil moisture, and there was negative correlation between the abundance of omnivorous arthropods and soil temperature and soil total carbon. (4) The partial redundancy analysis (pRDA) results showed that soil moisture was the key factor driving the distribution of functional groups of ground-active arthropods between seasons. In conclusion, there was unique different distribution of functional groups of ground-active arthropods in L. barbarum plantations along with the seasonal timing in arid oasis of Ningxia, while the difference of functional diversity was little. It was suggested that there was a sensitivity of abundance and richness distribution of each functional group to seasonal changes, whereas there was a relatively stable distribution of functional diversity between seasons.