A packet data processing apparatus of a wide-band wireless local loop (W-WLL) system includes a local area network (LAN) controller for performing an interface with a LAN and transmitting and receiving a packet data. The system further includes an high-level data link control (HDLC) controller for transmitting and receiving a packet data to and from a subscriber wireless connection unit through an HDLC channel, a dynamic random access memory having a first buffer for storing a mobile image packet data transmitted between the HDLC controller and the LAN controller and a second buffer for storing a packet data other than the mobile image, and a CPU for performing the corresponding control function of a packet data routing unit. Buffers are utilized and managed separately for transmitting mobile image data and general data from the packet data routing unit of the W-WLL system to the Internet.