A method of boron-contained wastewater treatment includes the following steps. Pretreatment: Mix a boron-contained wastewater with hydrogen peroxide for reaction at pH 8-12. Precipitation: Add n moles of barium compound into the pretreated boron-contained wastewater to provide perborate precipitation at pH 8.5-12. The number n is obtained from an equation of n=([B]*a+[NO3]*0.01+[F]*0.01+[CO3]*1+[SO4]*1)*V wherein a is ranged from 0.6-0.9. [B], [NO3], [F], [CO3], and [SO4] are molarities of boron, nitrate ion, fluoride ion, carbonate ion, and sulfate ion of the boron-container wastewater. V is the volume of the boron-container wastewater. A fluidized bed reactor is used.