According to the present invention, a reversed phase non-surfactant microemulsion formed from an n-hexane/isopropanol/water three-component system is adopted as a soft template, a microemulsion double drop method is used to prepare a flower ball-like layered bimetal hydroxide having a high specific surface area, and methyl orange is used to simulate anionic contaminants in water so as to investigate the adsorption properties of the prepared LDHs and the calcined product LDO; and the prepared Ni-Al-LDHs having the flower ball-like microstructure has the large specific surface area and provides good adsorptive removal effects on anionic contaminants in water, the process is simple, the reaction condition is mild, and the cost is low.