A method for regenerating granular activated carbon by arc initiation and discharge, the method comprising steps of: the granular activated carbon continuously flowing through a heating passage; and applying a direct current, DC, to two electrode plates in the heating passage, wherein the voltage of the DC is calculated by the voltage formula U = ηρcq m ΔT 1 + 2 q m α + q m + βd p l S, here, ρ is resistivity of the granular activated carbon, c is specific heat capacity of the granular activated carbon, q m is mass flow of the granular activated carbon in the heating passage, Δ T is target temperature rise value of regenerated activated carbon, d p is equivalent particle size of the granular activated carbon, l is distance between the two electrode plates, S is area of each of the two electrode plates, η is a dimensionless coefficient in a range of 1 to 5, a is an empirical parameter which is expressed by a formula of a = xwlρ m and has a unit of kg/s, here, x is an adjustment parameter with dimension m/s and is in range of 0.002m/s to 0.01m/s, wis facing width of the two electrode plates, ρ m is bulk density of the granular activated carbon, β is an empirical parameter in a range of 200m -1 to 800m -1, wherein: the granular activated carbon tumbles, collides and separates with each other in the heating passage during transportation, electrons are excited to pass through a potential barrier to form field emission and impact ionization, resulting in arc initiation; the arc initiation is conducive to current conduction and heat release, and greatly reduces the resistance of an activated carbon access circuit, so that under a combined action of conductive Joule heating and arc heat release, the activated carbon heats up rapidly and an adsorbate is pyrolyzed by high temperature, thereby achieving regeneration. the granular activated carbon continuously flowing through a heating passage; and applying a direct current, DC, to two electrode plates in the heating passage, wherein the voltage of the DC is calculated by the voltage formula U = ηρcq m ΔT 1 + 2 q m α + q m + βd p l S, here, ρ is resistivity of the granular activated carbon, c is specific heat capacity of the granular activated carbon, q m is mass flow of the granular activated carbon in the heating passage, Δ T is target temperature rise value of regenerated activated carbon, d p is equivalent particle size of the granular activated carbon, l is distance between the two electrode plates, S is area of each of the two electrode plates, η is a dimensionless coefficient in a range of 1 to 5, a is an empirical parameter which is expressed by a formula of a = xwlρ m and has a unit of kg/s, here, x is an adjustment parameter with dimension m/s and is in range of 0.002m/s to 0.01m/s, wis facing width of the two electrode plates, ρ m is bulk density of the granular activated carbon, β is an empirical parameter in a range of 200m -1 to 800m -1, wherein: the granular activated carbon tumbles, collides and separates with each other in the heating passage during transportation, electrons are excited to pass through a potential barrier to form field emission and impact ionization, resulting in arc initiation; the arc initiation is conducive to current conduction and heat release, and greatly reduces the resistance of an activated carbon access circuit, so that under a combined action of conductive Joule heating and arc heat release, the activated carbon heats up rapidly and an adsorbate is pyrolyzed by high temperature, thereby achieving regeneration.