The invention discloses a mixed 
signal arrival direction 
estimation method based on a co-prime array, and the method comprises the following steps: collecting the 
array element distribution information of a receiving end antenna co-prime array, and roughly estimating the number of 
signal sources; carrying out dimension expansion on the received 
signal by utilizing the circularity and non-circularity characteristics of the transmitted signal, calculating an 
autocorrelation matrix of the dimension expansion signal, and reconstructing the 
autocorrelation matrix into a vector; estimating a signalarrival direction by utilizing a 
covariance matrix obtained after spatial 
smoothing; taking out a plurality of 
estimation directions with the best 
estimation performance, and estimating the corresponding signal power; and calculating an 
autocorrelation matrix of the original received signal, reconstructing the autocorrelation matrix into a vector, deleting components corresponding to the non-cyclic signal from the vector, and estimating the 
direction of arrival of the cyclic signal through spatial 
smoothing operation and by using a MUSIC 
algorithm on the obtained 
covariance matrix. According to the invention, the 
array performance can be further enhanced, and more signal sources can be distinguished by fewer array elements.