Abstract: Considering the problem that the initial phase value is difficult to estimate which may consequently cause the low precision of direction-finding result with spatial spectrum estimation, in this paper a direction-finding method with spatial spectrum estimation using less channel quasi calibration is studied based on classic multiple signal classification (MUSIC) algorithm. In this method a calibration source is added in each channel, so that initial phase difference of each two channel can be achieved, and its effects to the calculation of covariance matrix be decreased. This method is applied in the direction-finding antenna with five elements and three channels. Test results show that with this method can realize the direction finding of single signal and double signals in complex scenes. Under the condition of low signal to noise ratio (SNR), the direction finding error can still be kept at about 3.5°, and the direction finding accuracy is high. The direction finding results are basically consistent with the direction finding results of the whole channel.