Electrolytic codeposition technique was adopted in the deposition of Ni-Co-Al2O3 coating on the stainless substrate, using nickel alloyed with iron as the binder phase with Al2O3 as dispersed particles. The results indicated that the deposit with Al2O3 nanoparticles was level and compact; the crystal-planes of the deposit were (111), (220) and (200). The resistivity of deposit was about 30 μΩ•cm. when the Co(wt.%) ranged from 10% to 50% in the deposit, the electrodeposit Ni-20%Co-Al2O3 has a strong paramagnetism effect with the smallest coercivity of 2.75×10-2 A/m. The remanence showed a monotonic decrease with the increasing iron content in deposit. Which proved that the electroformed NiCo-Al2O3 alloy has good electromagnetic property and higher corrosion resistance than those of electroforming Ni-Co alloy. It is a promising material in the fabrication of micro sensor.