This paper introduces a new method about the downlink power allocation in LTE system, first, eNB indicates the downlink power allocation information through MAC Control Element, second, UserEquipment calculates Energy Per Resource Element of Physical Downlink Shared CHannel Resource Element according to the downlink power allocation information, finally, UserEquipment use the new Energy Per Resource Element to decode. The advantage of the method is that processing delay is less, and it improves performance of downlink transmission system.