There are not so many researches that represent the whole behavior of a waterfall from the lip to the basin, especially there have not be reported the study that simulates the soaring up of the spray cloud, which appears from the water stream. In this paper, we propose a method that simulates the soaring up of the spray cloud into the air by considering the density difference of the air. The method divides a waterfall into 3 parts: water streams, splashing spray and spray cloud, and an appropriate equation is applied to each part. As a result, we can present not only waterfall but also splashing spray that appears from the waterfall, and spray cloud that flows around the waterfall. Especially, we simulate the waterfall behavior by considering rising-up airflow caused by the density difference of the air, and the terrain around the basin.