Beta distribution has become the main model to establish Wind Power Forecast Conditional Error (WPFCE) by its own characteristics. At present, most of the research results on Beta distribution modeling are focused on energy storage planning and economic dispatch. Facing the complexity and variability of WPFCE, there are few studies on the factors affecting the applicability of Beta distribution. In order to fill the shortcomings, the following work has been done in this paper. Firstly, the parameters and morphological characteristics of Beta distribution have been studied. Then paper gives the non-standard definition of conditional errors, the interquartile range method of outliers, and the indicators and steps for assessing the applicability of Beta distribution based on these characteristics. Finally, according to the actual power data of different capacities, the applicability simulation of Beta distribution under the influence of key factors such as partition numbers, outliers detection, estimation methods and power characteristics is completed, and the changing rules of Beta applicability and some empirical criteria are summarized according to the simulation results.