The problem of efficiently shaping downlink data bursts into rectangles and packing them in the OFDMA subframe is not addressed by the IEEE 802.16 standard, and is left as an implementation issue. In this paper, we propose a linear complexity bursts packing algorithm to maximize radio resources usage on the OFDMA downlink. Our scheme shapes the bursts into identical width, places them in column direction and maximally fills the columns by shifting the bursts on different columns. By simulation, we show that the scheme can push the radio resource usage over 95%, which is on average 20% improvement compared with the simple 2D fixed-bin strip packing and 8% improvement with the exhaustive search. Moreover, the proposed scheme is also power-efficient, because subscriber stations (SSs) do not need to receive a large aggregated burst created for packing problem complexity reduction.