As the complex electromagnetic environment becomes the main characteristic of modern war, military training under complicated electromagnetic environment is taken seriously and the complex electromagnetic environment has become one of research hot spots. On the degree of complex electromagnetic environment for scientific classification, correct measures, so as to form a complete set of reflect the internal logic structure of complex electromagnetic environment change rule and the external display system, in order to accurately image analysis, grasp and control the battlefield electromagnetic momentum, has become the top priority. In this paper, the method of the cosine vector included angle is used to evaluate complexity of complex electromagnetic environment. Evaluation index system is needed to set up to assess the complexity of the electromagnetic environment. In this paper short-wave communication is evaluated by the rate of abnormal signal, large signal rate, time possession, spatial coverage, channel occupancy degrees, the average power spectral density and the Background noise intensity. We use the example in the literature [9] for solving and analysis. Test data of the shortwave receiver intercepted in accordance with the frequency spectrum is divided into three test evaluation, respectively 15.0015.33MHz, 15.3315.66MHz, 15.6615.99MHz. Electromagnetic environment of three days in each frequency band is used the object of assessment, Seven indicators' data of Three evaluation object is gotten. By formula (10) measurement of electromagnetic environment complexity in 3 bands is gotten, Respectively 0.9998, 0.6999 and 0.3701., the results are basically identical with the results in the literature [9]. In this paper, the complexity of the complex electromagnetic environment assessment is quantified by using Method of the cosine vector included angle. Complexity quantitative evaluation of the short wave electromagnetic environment has been carried out to verify the complexity of the instance. The instance results show that the Method of the cosine vector included angle can be used to assess the complexity of the electromagnetic environment. As to whether this method can be used to calculate the complexity of the other types of electromagnetic environment, further research is needed.