The present application discloses a feed-forward amplifier device and the method thereof. The device comprises: a splitter for splitting an input signal into two portions; a non-linear amplifier for amplifying the input signal and producing inter-modulation products; a carrier canceling unit for generating pure inter-modulation products; a linear amplifier for amplifying the pure inter-modulation products; and a coupler for generating final output signal by counteracting the inter-modulation products with the amplified pure inter-modulation products; wherein the splitter and the carrier canceling unit are provided in digital base band. According to the present disclosure, pure inter-modulation products can be generated and adjusted more flexibly and more accurately in digital base band, and hence ideal output signal may be generated.