A plant denitrification device includes a holding tank, at least one planting plate and at least one light source, wherein the holding tank is in a long shape, has a top opening communicated with its interior, and is internally provided with a liquid supply source, and the liquid of the liquid supply source can be water or diluted nutrient solution.The planting plate is placed on the holding tank and moves along the long axis of the holding tank under external force； the planting plate has at least one planting area for placing plants, the planting area should be open to the top, and the roots of the plants contact the liquid supply source； the light source is arranged above the holding tank along the long axis of the holding tank.Therefore, the light source provides light for plants to cooperate with each other, and the liquid cleans the roots of plants, so that plants can fully decompose nitrate.一種植物去硝酸鹽裝置，包括有一容槽、至少一栽植盤與至少一光源，其中，該容槽係呈長形，其具有一頂部開口與其內部相通，且其內部設置一液體供應源，液體供應源之液體可為水或稀釋的營養液。該栽植盤係置於該容槽上，且該栽植盤係受外力而沿該容槽之長軸向移動；該栽植盤具有至少一栽植區供放置植物，該栽植區對應該頂部開口，且植物的根部接觸該液體供應源之液體；該光源沿該容槽之長軸向設置於該容槽上方。藉此，由光源提供光線予植物行光合作，且液體清洗植物的根部，讓植物可以充分分解硝酸鹽。
