Abstract: This article studied the smelting process and machinability of BN-type free cutting steel. Samples with different B and N contents were prepared by cold crucible induction melting. The precipitation of main inclusions in sample was investigated by theoretical calculation. After that, the morphology, size and composition of BN type inclusions were analyzed. The mechanical test and machining test of the samples were carried out. It is found that adding B and N elements into steel can improve the machinability of the steel, but do not affect the mechanical properties.