The invention discloses a high-tenacity low-hydrogen alkaline welding rod which comprises a coating and a welding core, wherein the coating comprises, by weight, 38%-44% of marble, 20%-25% of fluorite, 3%-5% of zircon sand, 1%-5% of ferrosilicon, 10%-15% of ferrotitanium, 5%-7% of mid-carbon ferromanganese, 2%-4% of titanium dioxide, 3%-6% of mica, 1.5%-2% of microcrystalline fiber, 1.2%-1.8% of nickel powder, and 1%-1.5% of misch metal, wherein sum of weight percentages of all components is 100%. The invention further discloses a preparation method of the high-tenacity low-hydrogen alkaline welding rod. The preparation method of the high-tenacity low-hydrogen alkaline welding rod includes the steps: enabling coating materials and K-Na mixing water glass to be mixed, crushing the mixture into a power ball with a cylindrical shape, putting the power ball into a pressing coating machine, coating the power ball with the cylindrical shape on a H08A welding core to form the welding rod, and then grinding the head and the tail and getting the high-tenacity low-hydrogen alkaline welding rod after drying. When the high-tenacity low-hydrogen alkaline welding rod is used for welding high-strength steel, no preheating is needed before welding, no heat treatment is needed after welding, content of diffusible hydrogen of deposited metal is controlled effectively, and the preparation method is simple.