Abstract: Cobalt oxalate powder is the main raw material for preparation of cobalt powder and cobalt oxide.The cobalt oxalate powder was synthesized by liquid-phase precipitation process with CoSO↓4，(NH↓4)↓2C↓2O↓4 and H↓2C↓2O↓4 as raw materials.The effect of different process conditions，such as the precipitators，the feeding methods，reacting temperature and reactant concentration etc.on the particle size and yield of CoC↓2O↓4 were studied.The result indicated that using (NH↓4)↓2C↓2O↓4 as a precipitator，uniform CoC↓2O↓4 with the particle size of 1.1 μm could be prepared at 50 ℃ through a solid-liquid feeding wayi.e.rapidly adding solid (NH↓4)↓2C↓2O↓4 into liquid CoSO↓4 solution.\〗.Whereas，the larger particles of CoC↓2O↓4 with a yield of 99.6% could be synthesized at 50 ℃ through a liquid-liquid feeding wayi.e.adding (NH↓4)↓2C↓2O↓4 solution into liquid CoSO↓4 solution.\〗.