Abstract: Vanadium-titanium magnetite from Panxi was superfinely crushed by high pressure grinding roller. The particle size characteristics of the crushed product from different crushing processes were analyzed, and the modification of the work index of ball mill and emerging of the micro-crack by different crushing manner were studied. The results showed that, in crushed products, the reduction ratio increases and the size distribution becomes more uniform with increasing of the pressure on roller surfaces. The particle size decreases but uniformity reduces with increasing of the edge products circulating mass. And the fine fraction content of crushing products from -3.2 mm classification closed-circuit by HPGR increases obviously compared with that by Jaw Crusher and particle size distribution is more uniform. Large amount of intracrystalline cracks and cleavage cracks are generated in vanadium-titanium magnetite crushed by HPGR, which makes the Bond work index of ball mill (objective particle size is 0.074 mm) of vanadium-titanium magnetite 14.05% lower than that by Jaw Crusher.