The invention relates to a sacrificial anode structure. The sacrificial anode structure comprises a checking head, a plug screw and a corrosion block. Both the plug screw and the corrosion block are made of metal. The activity of the corrosion block is higher than that of the plug screw. A first hole and an indication channel are formed in the plug screw. A second hole is formed in the corrosion block. The plug screw and the corrosion block are fixedly connected. The first hole, the second hole and the indication channel are mutually communicated. The checking head is fixedly connected to the end of the plug screw. The sacrificial anode structure is simple, and the requirement for the manufacturing level is quite low; the corrosion state of a sacrificial anode can be known at regular times conveniently and rapidly, and timely monitoring and replacing are conducted; meanwhile, an insulation material is used between the plug screw and the corrosion block so that dissimilar metal contact corrosion between the plug screw and the corrosion block can be avoided, and the service life of the sacrificial anode is prolonged.