To counter main lobe jamming, an algorithm based on blind source separation (BSS) and blocking matrix (BM) joint processing is proposed. The arrival of main-lobe jamming angel is estimated; the BM is used to prevent main-lobe jamming receiving; the joint approximation diagonalization of eigen matrices (JADE) is used to separate sources. The experiment of simulation indicates that the new algorithm has greater peak SNR than BSS when the jamming locates in 1/2 beam width, and improves the radar detection performance largely. Even there exists a main-lobe interference direction estimation error, the new algorithm still has good anti-interference ability.