Abstract: Electromagnetic environment is dynamic and evolutional. Aimed at this characteristic an improved method of the quantificational evaluation on the complexity is presented. Among the index set of evaluation, the rate of variable information is adopted as the scale parameter to reflect the evolutional characteristic of electromagnetic environment. Using the technique of cluster and Hough transformation, the rate of variable information is quickly abstracted from the timefrequency distribution of scanner data and integrated into the acquisition of evaluation sample. Finally, the adaptivenetwork based fuzzy inference system is introduced to implement the quantificational evaluation on the complexity of electromagnetic environment. The experimentation demonstrates the validity of the proposed method.