The invention provides a superlow-hydrogen, high-strength and high-toughness alloy tool steel welding electrode with outstanding anticracking performance, which comprises a core wire and a welding electrode covering composition, wherein the electrode covering composition comprises the following components in percentage by weight: 35 to 45 percent of marble, 20 to 30 percent of fluorite, 2 to 4 percent of titanium white, 8 to 13 percent of ferrotitanium, 0.5 to 1.5 percent of alkali, 3 to 6 percent of metal chromium, 4 to 8 percent of metal manganese, 4 to 8 percent of nickel powder, 3 to 6 percent of ferromolybdenum, 2 to 6 percent of rare earth silicon, 2 to 6 percent of quartz and 2 to 6 percent of feldspar. The core wire is made of H08A steel or H08E steel, and potassium sodium mixed water glass is used as a bonder. The alloy tool steel welding electrode can be used as a superlarge-section alloy tool steel (5CrNiMo) structure welding electrode which used to lack and can be used for welding other high-strength alloy steel structure products. The welding electrode has an excellent welding process property, high welding strength, rigidity, plasticity and ductility.