The present invention relates to a hydroponic system, which comprises at least a hydroponic tank and at least a level adjustment tank. The hydroponic tank and the level adjustment tank are respectively provided with at least a carrier for carrying or growing plants and at least a float. Each carrier and float is linked by a linkage mechanism. The summed fluid level of the level adjustment tank is much smaller than that of the hydroponic tank, so by filling or discharging a small amount of an adjustment solution in or out of the level adjustment tank, the height of the float in the level adjustment tank can be altered with the elevation of the fluid level； as such, the level adjustment tank can greatly save the required water amount and shorten the operation time of a water pump.
