We analyze LED-allocation algorithms for high-speed parallel wireless optical communication system that we have developed. It enables up to gigabit-class communication using two-dimensional transmitter composed of LED array, and two-dimensional receiver composed of lens and image sensor. However, there are some interference problems when the allocation of packets to LEDs is not good. Considering these problems, we propose new LED-allocation algorithms to improve the affection of interference. In this paper, we analyze the link of parellel wireless optical communication system and show the effectiveness of our proposed algorithms by simultaion.