Differently from fly ash, the bottom ash produced from incinerated urban solid waste has been treated as an industrial waste matter, and almost reclaimed a tract form the sea. If this waste material is applicable to foam concrete as an fine aggregate, however, it may be worthy of environmental preservation by recycling of waste material as well as reducing self-weight of high-rising structure and long-span bridge. This research has an objective of evaluating the effects of application of bottom ash on the mechanical properties of foam concrete. Thus, the ratio of bottom ash to cement was selected as a variable for experiment and the effect was tested by compression strength, flexural strength, absorption ratio, density, expansion factor. It can be observed from experiments that the application ratios have different effects on the material parameters considered in this experiment, thus major relationship between application ratio and each material parameter were finally introduced. The result of this study can be applied to decide a optimal mix design proportion of foam light-weight concrete while bottom ash is used as an fine aggregate of the concrete.