The electrochemical and microstructural properties of cast MlNi3. 8C0. 6Mn0.55Ti0.05 have been investigated in detail. The results show that the initial activation and the low-rate discharge capacity are promising, but the high-rate discharge capacity and the discharge voltage plateau are to be improved for this alloy. Segregation, mainly Ti(NiCoMn),was detected using in situ X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). Ti (NiCoMn) segregation makes the alloy easy to pulverize, and consequently decrease the cycle stability of the alloy. The segregation should be avoided to make the full use of Ti.