The invention relates to a smelting molding device for making gradient optical glass and a method for making the gradient optical glass. The device comprises a smelting furnace, wherein the smelting furnace is provided with a first thermal chamber and a second thermal chamber, the interior of the second thermal chamber is heated to a smelting temperature suitable for smelting frit during work, the interior of the first thermal chamber is at a molding temperature which is lower than the smelting temperature during work, a smelting crucible for smelting the frit is arranged in the second thermal chamber, a molding boat for receiving a frit solution from the smelting crucible is arranged in the first thermal chamber, and a leaking pipe for conveying the frit solution from the smelting crucible to the molding boat is arranged at the bottom of the smelting crucible. Mixed batches with different optical properties and close expansion coefficients below 300 DEG C are smelted by density in a gradually decreasing order and sequentially poured in the molding boat. The gradient optical glass with continuously gradually varied refractive indexes is obtained after cooling the molding boat.