The invention discloses a multi-finger gate structure-based terahertz radiation source device and a regulation and control method thereof. The terahertz radiation source device comprises a channel layer, a channel providing layer, a source and a drain; a two-dimensional electron gas (2DEG) channel is generated inductively in the channel layer; two groups of gates are alternately arranged on the channel providing layer; when different voltages are respectively applied to the two groups of gates, the concentration of 2DEG in channel regions located below the two groups of gates and the concentration of 2DEG in channel regions located right below areas between any two adjacent gates are different; 2DEG concentration difference interfaces are formed between the channel regions; and if a voltage is loaded between the source and the drain, a standing wave oscillation structure with periodic concentration difference is constructed in the channel; and therefore, terahertz radiation is generated. The terahertz radiation source device has the advantages of easiness in excitation, high power, modulatability, convenience in miniaturization, light weight, easiness in integration and the like. The radiation frequency of the terahertz radiation source device can be adjusted within the range of 0.3THz-1.9THz. The terahertz radiation source device is suitable for being widely applied to multiple fields.