[Objective] The water conservation function of litters of artificial Pinus tabuliformis forests in the Ziwuling forest region of the Loess Plateau was determined in order to provide a theoretical basis for function-oriented stand improvement.[Methods] In August 2021, artificial Pinus tabuliformis forests with six stand densities (2 222, 3 200, 4 802, 6 250, 7 503, 9 286 plants/hm²) were selected in the Lianjiabian Forest Farm in Ziwuling, Heshui County, Gansu Province. The coordinate comprehensive evaluation method was used to evaluate the water conservation function of P. tabuliformis forests.[Results] ① The thickness and volume of litters ranged from 2.78 to 7.30 cm and from 14.97 to 52.41 t/hm², respectively. With the increase of stand density, the thickness and volume of litters showed a "single peak" change, with the peak appeared at 4 802 plants/hm². ② The maximum water-holding rate (192.98%) and effective interception rate (152.04%) of litter for the 3 200 plants/hm² stand were higher, while the maximum water-holding capacity (101.46 t/hm²) and effective interception amount (67.92 t/hm²) of litter for the 4 802 plants/hm² stand were excellent. The semi-decomposed layer played a major role in the precipitation interception process of litters. ③ The water-holding rate/amount, water absorption rate, and soaking time of litters showed logarithmic responses (R²>0.956, 0.962) and a power function response (R²>0.998), respectively. ④ The water conservation function of litters was better when the density of the P. tabuliformis forest was 4 802 plants/hm².[Conclusion] When only considering the water conservation function of litters of an artificial P. tabuliformis forest, the density of the forest should be 4 800 plants/hm². In the future, research on the canopy and soil layer of the P. tabuliformis forest should be strengthened. The soil moisture vegetation bearing capacity and the water utilization law of the forest should be comprehensively considered to determine the stand density of the forest that provides the best water conservation function.