L(r) function and g(r) function (the derivation of Ripley′s K(r) function) are used in analyzing the spatial pattern and spatial correlation of Haloxylon ammodendron population in different developmental stages in Gurbantonggut desert. The L(r) function revealed an aggregated distribution trend as a whole and the scale ranges from 0m to 25m, while g(r) function revealed an aggregated distribution mainly within 3 meter′s scale, beyond which the distribution becomes smooth and the aggregation trends extended to no more than 10m. With the development of the Haloxylon ammodendron from seedling and sapling into the adult, both the L(r) function and g(r) function show that the distribution trend changes from aggregated to stochastic or even uniform distribution in some scale. As to the spatial correlations, positive correlation is shown in both the L(r) and the g(r) functions, but the scale is larger in L(r) function than that in g(r) function. In L(r) function, the relationship between seedling and sapling or the adult tree is positive within 15m′s scale, while in g(r) function positive correlation is shown between the seedling and the sapling within 5m′s scale, whereas negative correlation is shown between the sapling and the adult within 10m′s scale. That is to say, the greater the difference in the age of the plants, the weaker the positive correlation is shown. As a balance confined by the amount and the spreading of the seed, aggregated distribution and positive spatial correlation in seedlings are beneficial to the survival and development of the Haloxylon ammodendron population. The distribution pattern of the Haloxylon ammodendron population is also affected by topography. The aggregative intensity and association in Kuitun interdune are greater than that in Wujiaqu but their ramp difference is small. This shows that topography has an indirect influence on the distribution pattern of the Haloxylon ammodendron population because of its redistribution function to all the resources. On the whole, in analyzing the spatial pattern and spatial correlation of Haloxylon ammodendron population different results are shown in L(r) function and g(r) function. The maximum value in L(r) function shows the typical aggregation scale while the first maximum value in g(r) function shows the typical distance between plants. The spatial patterns shown in L(r) function and g(r) function are consistent in small scale, but differ a lot in large scale. In small scale the result shown in g(r) function is closer to the reality and it truly reflects the "key scale" in the correlation between the spatial pattern and the developmental stage of the Haloxylon ammodendron population. The result shows that to adapt to the unfavorable environment, aggregated distribution which is beneficial to the survival and development of the individual, is the main trend for the Haloxylon ammodendron population. Consequently, the combination of the L(r) and g(r) is favored in reflecting the spatial correlation among plant individuals.