The present invention provides a power battery and a positive electrode plate thereof. The positive electrode plate includes a positive current collector and a positive active material layer formed on the positive current collector. The positive active material layer contains a mixture of lithium iron phosphate and FeF3, or a mixture of lithium iron phosphate and LiFe2F6, or a mixture of lithium iron phosphate, FeF3 and LiFe2F6. FeF3 or LiFe2F6 has a high gram capacity of more than 200 mAh/g and has a charge and discharge interval close to that of lithium iron phosphate, which can improve the energy density and the safety performance of the power battery.