The noncentral F distribution is a commonly used probability distribution. This distribution is closely related to the chi-square distribution. It is derived from a combination of a chi-square distribution and a noncentral chi-square distribution. The noncentral F distribution is widely used in statistics, especially in analysis of variance and regression analysis. In addition, the noncentral F distribution is commonly applied in engineering fields, such as signal processing. Therefore, it is necessary to study the noncentral F distribution. Its cumulative distribution function can be expressed as an infinite series, and therefore, it can only be approximately calculated. Existing research also lacks investigation into the maximum term of this infinite series. In this article, the range of the location of the maximum term in this infinite series is derived through mathematical derivation. This article also conducted numerical experiments to validate the theoretical results. The experiments demonstrated the correctness of the theoretical results. The numerical experiments show that the upper bound of the results derived in this article is very close to the actual position of the maximum term in the infinite series. By performing simple calculations, we can easily determine the distribution range of the maximum term in infinite series of noncentral F cumulative distribution function. This will help to further investigate the patterns of the cumulative distribution function of the noncentral F distribution. Determining the location of its maximum value helps in finding more convenient and accurate approximation methods for the cumulative distribution function of the noncentral F distribution. Furthermore, this method has a certain degree of generality and is expected to be applied to the cumulative distribution function of other distributions with similar forms.