Disclosed is a method for preparing a lithium metal phosphate represented by the following Formula 1 by using a mixture of a metal (M) with a metal oxide containing the same metal: LixMyPO4  [Formula 1] wherein M is a transition metal element selected from Group 3 to 12 elements in the Periodic Table, Mg, Al, Ga and B; 0.05≦x≦1.2; and 0.8≦y≦1.2. Also, an electrode comprising the lithium metal phosphate as an electrode active material, and a secondary battery comprising the electrode are also disclosed.