The invention provides an under-well evaluating apparatus for sacrificial anode material. The under-well evaluating apparatus comprises a non-connection hanging parcel set, connection hanging parcel sets, sacrificial anode blocks, product collection tanks and an oil pipe short joint, wherein the upper end of the oil pipe short joint is covered with an upper locking sleeve and the lower end is covered with a lower locking sleeve; the external side of the oil pipe short joint is covered with an insulated lining sleeve; the external side of the insulated lining sleeve is orderly covered with the non-connection hanging parcel set, the connection hanging parcel set and the sacrificial anode block from the top to the bottom; the upper and lower ends of the insulated lining sleeve are both connected with an insulated cushion sheet; the non-connection hanging parcel set is connected with the connection hanging parcel sheet sets via insulated cushion sheets; the connection hanging parcel sheet sets are connected with the sacrificial anode blocks via connection screws; and the lower ends of the sacrificial anode blocks are provided with the product collection tanks. The under-well evaluating apparatus for sacrificial anode material is simply structured, requires low cost, can be easily applied and has short evaluating period; problems that sacrificial anode corrosion products are loosened, easy to be flushed by under-well fluid, peeled and uneasy to be collected can be solved; and protection effect of the sacrificial anode material under different medium conditions can be evaluated.