The invention relates to a digital electronic ballast and a control method therefor, comprising a power section and a control section. The control section insists of a microcontroller MCU, a drive curcuit, a half bridge output circuit, a ballast inductance, an igniting circuit, a current sampling circuit, a voltage sampling circuit and an accessory circuit; the MCU selectively realizes digital sweep frequency resonance ignition, digital constant power control, hybrid modulation eliminating acoustic resonance, digital time-sharing stepped light-regulation and fault protection according to a control software. All the functions of the invention basically are finished by a MCU and a control software thereof with the easiest circuit structure. A plurality of functions which looks independent are amalagamated organically in software process of the MCU, but common denominators thereof need change of output frequency to realize functions respectively by hardwares completely, make the circuit be more complex. The invention has high relizbility and low cost.