Most metal equipment in seawater or the cathodic protection of the interior floor of a crude oil storage tank cannot be used in a soil environment with low chloride content. The electrode potential of the aluminum sacrificial anode is -1.05 volts, and the capacitance of the aluminum sacrificial anode decreases with the increase of temperature when the ambient temperature is higher than 49 degrees Celsius, which can be referred to the formula: Z=2500-27 (T-20), the working temperature of the T anode, unit ° C. In saltwater environments, the current capacity of aluminum sacrificial anodes may be reduced by half. Aluminum sacrificial anodes can be fixed directly to the structure of the equipment to be protected without the need for other substances as fillers.