A communication device for handling a power headroom report (PHR) for multiple time intervals comprises a storage device for storing instructions and a processing circuit coupled to the storage device. The processing circuit is configured to execute the instructions stored in the storage device. The instructions comprise determining a PHR for a plurality of time intervals in a time interval according to a PH level of one of the plurality of time intervals, wherein the plurality of time intervals comprises at least one scheduled time interval; and transmitting the PHR to a network.