In this paper, we introduce a new Adaptive Physical Resource Block Design for Enhancing Voice Capacity over Long- Term Evolution (LTE) Downlink in Professional Mobile Radio (PMR) Context. In this method, we reorganize the structure of the Physical Resource Block (PRB) to optimize the voice capacity of LTE downlink in the PMR Context. Available PRBs in each subframe is reorganized into a number Sub Physical Resource Blocks. The number of control symbols can be selected flexibility. The proposed method allows reducing both data overhead and control overhead issues for Voice over LTE downlink in PMR context. On average, the voice capacity gain were shown to have about 117.2% in comparison with the standard LTE