Abstract: The cloud model has established the uncertain transformation between qualitative concepts and their quantitative description.The universality of Gauss distribution and Gauss membership function prepares the ground for the universality of Gauss cloud model,and up to now the theory of cloud model and its applied researches have mainly focused on Gauss cloud model.In this article the uniform distribution was introduced into cloud model and Gauss cloud model was extended,thus resulting in two models:uniformly distributed cloud model and uniform Gauss cloud model which offer a new way for uncertainty description.Finally,the multi-dimensional uniform Gauss cloud model was used to simulate the growth process of fractal tree.The result indicates that the cloud model can be used to effectively simulate the fractal phenomena in nature.

Key words: Cloud model,Gauss cloud,Uniform distribution