When oceanic lidar detects the underwater target, the detection depth will be influenced by the wavy surface. The spatial distribution of the photons on the target plane has already become the focus of the research. Most of the work that has been done is about radial distribution of photons in the small-radius region, while research about the photon diffusion on the target plane in wider region is very little. Based on Monte Carlo method, through the comparison between abandon and select sampling and transform sampling, the radial distribution of photons in big-radius region has been analyzed. The results show that, for the same radius, the radial distribution of the photons′ relative energy and the wind speed follow some rules. That means the randomness due to the wind speed is not completely random, there are some rules too. Meanwhile, the comparison between abandon and select sampling and transform sampling shows that transform sampling is only as an approximation, and its result is not as accurate as abandon and select sampling.