Abstract: Abstract: Shelter forest is an important part of the vegetation ecosystem in arid and semi-arid areas. It can change the airflow velocity and direction, reduce wind speed, and control quicksand. It plays an important role in improving the oasis ecological environment, protecting biodiversity, and promoting social and economic sustainable development. The density, height and tree species of the forest belts are the key factors that determine whether the forest belts can continue to exert the best protection benefits. To optimize configuration of shelter forest in arid areas, Salix matsudana, Artemisia ordosica and Haloxylon ammodendron were selected to design the models of A-type (high density), B-type (medium-density), C-type (low-density) arbor-shrub mixed forest belts according to the density and principle of similarity. The forest belts of different densities were designed to 9 types of arbor-shrub mixed forest belts with three heights, according to the forest age (5, 10, 20 years). Wind tunnel experiments were carried out under the wind speed of 12 m/s and we observed 99 points in the forest belts with a measurement height of 2 cm to analyze the wind speed frequency, wind speed flow field, probability density and effective windproof area of the arbor-shrub mixed forest belts in different configurations. The results showed that there were significant differences in wind speed and flow field on the leeward side of arbor-shrub mixed forest belts in different configurations. The wind speed at the same position decreased, while the airflow becomes stable as the height of the constant density forest belt increased. The wind speeds of high-density, medium-density and low-density forest belts of five years old were concentrated at 6.5-8.5, 7.2-7.6, 7.5-8.5 m/s, respectively, whereas the wind speeds of three-density forest belts of 20 years old were concentrated at 2.5-3.5、4-5、4.5-5 m/s, respectively. The forest belt density was an important factor that affects the forest belt's windproof performance when the forest belt height was not high. The average wind speed of the 10-year-old medium-density forest belt was similar to the average wind speed of the 5-year-old high-density forest belt. Windproof effects of forest belts can be improved by increasing the forest belt density. The maximum wind speeds of the 10-year-old medium-density and low-density forest belts at the same height were similar to that of high density, but the minimum wind speeds were 5.88 and 7.27 times of the high density forest belt, respectively, indicating that the high-density forest belt had a significant effect on reducing wind speed, but the wind speed recovered rapidly with the increase of the forest belt distance. The optimum wind protection area of forest belts with different densities moved backwards with the increase of belt height. When the forest belt height increased, the advantage of forest belt density decreased. Therefore, the middle and high forest age and middle density arbor-shrub mixed forest belts can be the optimum ecological and economic benefits.