A hydroponic system consists of a hydroponic tank, a carrier or carriers for carrying or growing plants, a float or floats, and a supplementary lifting unit. The supplementary lifting unit includes a take-up mechanism having a small reel and one or multiple large reels configured subject to the circumference ratio of 1:&gE；1 so that increasing the fluid level in the hydroponic tank to lift or lower the float one unit-height causes the carriers and the plants thereof to be lowered or lifted one unit-height plus the height corresponding to the circumference ratio between the large reel and the small reel for enabling the roots, stems and leaves of the growing plants to be dipped in the nutrient solution in the hydroponic tank or exposed to the outside air.本案係一種水耕裝置，其係由一栽培槽、至少一浮體、至少一用以承載或植栽植物的載台及一輔助升降裝置所組成。該輔助升降裝置於栽培槽上方樞設至少一捲取機構，各捲取機構設有一小捲軸及至少一大捲軸，該小、大捲軸的圓周比為1：不小於1，且該小、大捲軸上所捲繞的第一牽引索及第二牽引索的活動端分別連接於浮體及載台；藉此，通過進水管或排水管向栽培槽注入或排放培養液，使培養液的原有液面水位及浮體每升高或下降一單位高度時，則可令各載台及其植物相對於現有液面水位以大、小捲軸的圓周比加上一單位高度的比例下降或升高，使該載台及其植物之根、莖、葉部可浸漬於培養液中，以全方位方式吸收生長所需的養分。
