The invention discloses an external radiation source radar direct wave recovery method adopting blind source separation. The method comprises the following steps that: (1) a linear array receives signals x1(n), ..., xN(n), and a digital wave beam is formed; (2) wave beam signals yS(n) of a reference radio station and wave beam signals y1(n), ..., yJ(n) of J interference radio stations are input into an instant ICA (independent composition analysis) blind source separation module, then output signals p0(n), p1(n), ..., pJ(n) of the blind source separation are sent to an ambiguity-resolving processing module, and obtaining the signal q(n) of the reference radio station; (3) yl(n) is input into a plurality FIR (finite impulse response) filters of a spatial domain-fast time domain module, two-dimensional self-adaptive filtering processing is carried out through a multi-dimensional spatial domain-fast time domain algorithm, and a monitoring channel signal z(n) is output and obtained; and (4) based on the signal q(n) of the reference radio station and the monitoring channel signal z(n), a time delay Doppler plane of a target is calculated. According to the invention, the sequence ambiguity problem of output signals of the blind source separation method is solved, and the reliable reference radio station direct wave recovery is ensured.