[Background] The fragile ecosystem in the Losses Plateau is facing the crisis of degradation at present, which seriously impede the development of local economy. Agroforestry system which can restore the ecological balance, reduce the soil and water loss amount thus increase the economic income has become the main agricultural practice recently in losses region of west Shanxi province. However, the unreasonable management for irrigation and fertilization in agroforestry system may also increase the interspecific competition, which may cause the reduction of yields even the occurrence of soil erosion. Therefore, it is essential to find a more effective and economical irrigation and fertilization method in agroforestry of this area to ease the interspecific competition and conserve both the moisture and soil. [Methods] An experiment of water and fertilizer coupling with 2 factors (irrigation and fertilizer) and 3 application rate levels was carried out in a typical apple*maize intercropping system in the loess region of Shanxi Province. The effect of different irrigation and fertilization regimes on soil moisture especially the spatial and temporal distribution at filling and maturing stage of maize were analyzed. There were 9 treatments in the study based on the irrigation and fertilization coupling (W₁F₁, W₂F₁,W₃F₁, W₁F₂, W₂ F₂, W₃F₂, W₁F₃, W₂F₃, and W₃F₃). The regimes were designed based on 3 irrigation levels: a) Low, (W1), 50% Fc (field capacity); b) Medium, (W₂), 65% Fc; and c) High, (W3), 85% Fc. The fertilizer levels were: F1, (N (289 kg/ ha) + P₂O₅(118 kg/ ha) + K₂O (118 kg/ ha));F₂ (N (412.4 kg/ ha) + P₂O₅ (168.8 kg/ ha) + K₂O (168.8 kg/ ha)); F₃(N (537 kg/ ha) + P₂O₅ (219 kg/ ha) +K₂ O (219 kg/ ha)); and CK (no irrigation and fertilization throughout the growth season). All irrigation and fertilizer application amount were set up based on the water and nutrients requirements for maize and apple trees in this area. [Results] The application of irrigation and fertilization enhanced soil moisture by 7.6% than CK at filling stage, and 10.9% at maturing stage. The maximum soil moisture achieved in W3F1 treatment at filling stage. There was no significant difference in soil moisture along the distances from the tree line to maize in the plot, suggesting that the reasonable irrigation and rtilization alleviated the soil water competition between different species in intercropping system. Moreover, the soil moisture decreased firstly with the increase of soil depth within 0 - 30 cm depth and then increased whereas the trend maintained constantly the soil moisture decreased with the increase of soil depth (0 - 60 cm) in CK. Accordingly, the application of water and fertilizer increased the soil moisture in deep soil layer (30 -60 cm) significantly at maturing stage. [Conclusions] According to the results in jointing-filling stage, the soil moisture (0 -60 cm) was optimal when the total irrigation and fertilizer amount were 1 300 m³ / ha and 525 kg/ ha, respectively. Consequently, the results of this study may provide theoretical basis and technical support for the local farmers to manage water and fertilizer in a more effective way for intercropping system in the loess region of western Shanxi Province.