The influence of the sudden change of the direction of arrival (DOA), the number of source signals and the signal pattern on the estimation of the number of emitters and the results of blind source separation (BSS) are analyzed. The number of source signals is estimated based on the information theory criterion, and the adaptive blind separation algorithm is used to separate the signals. The experimental results show that when the mixing matrix mutates, the number of sources cannot be estimated correctly by using the received data, and when the mixing matrix does not mutate, but the signal pattern mutates, the number of sources estimation algorithm can estimate the number of DOA accurately; If the mixing matrix does not change, the change of the signal mode in a certain direction of arrival will not have a negative impact on the blind separation of the signal, and the signal modes in different directions of arrival can be separated; if the mixing matrix does not change, the change of the number of signals in the array receiving signal will not have a significant negative impact on the signal separation results. The analysis results show that the study has a certain reference value for evaluating the application effect of the source number estimation algorithm and the blind source separation algorithm in the actual environment.