Disclosed is lithium iron phosphate having an olivine crystal structure wherein carbon (C) is coated on particle surfaces of the lithium iron phosphate, wherein, when a powder of the lithium iron phosphate is dispersed in water, water is removed from the resulting dispersion and the resulting lithium iron phosphate residue is quantitatively analyzed, a ratio of the carbon-released lithium iron phosphate with respect to the total weight of the carbon-coated lithium iron phosphate is 0.005% by weight or less. Advantageously, the olivine-type lithium iron phosphate is not readily separated through uniform thin film coating on the surface of the lithium iron phosphate and exhibits superior conductivity and density, since carbon is coated on particle surfaces of lithium iron phosphate in a state in which the amount of carbon released in water is considerably small.