Abstract: The  effect  of  main   element-0.015～0.070C,1.21～2.30Si,0.25～0.33Mn,0.013～0.018P, 0.008~0.017S,0.002～0.210Al in low grade cold rolled non-oriented electrical steel on core loss has been studied by the process of 50 kg vacuum induction furnace steelmaking - 100 mm×25 mm slab forging -2 mm strip hot rolled by 350 four high mill-0.5 mm strip cold rolled by 350 four high mil.Results showed that with increasing carbon,phosphorus, sulphide,manganese content in steel the core loss of cold rolled non-oriented electrical steel obviously increased; with in- creasing silicon content in steel the core loss decreased and as aluminum with nitrogen formed fine AlN particles to prevent grain growing up in steel,the core loss increased with increasing aluminum content in steel.