The invention provides a digital comprehensive regulation device for hydroelectric generating sets, and a control method thereof. The device comprises a controller, wherein the controller is respectively connected with a Hall current sensor, a Hall voltage sensor, a current conditioning circuit, a voltage conditioning circuit A and a voltage conditioning circuit B through analog input interfaces, and is respectively connected with a shaping circuit A, a shaping circuit B, a circuit-breaker auxiliary contact and a shaping circuit C through high-speed digital input interface; the controller is respectively connected with a pulse amplification circuit and a circuit breaker through high-speed digital output interfaces; and the controller is also respectively connected with a digital mixing module and an analog input module. The device can control and regulate the dynamic performances of generating sets by measuring and calculating the parameters of power networks and generators. The device integrates synchronization, speed regulation and excitation, has the characteristics of high control performance, short response time, programming easiness, debugging convenience, high execution speed and the like, and is particularly applicable to the comprehensive control over medium / small-size hydroelectric generating sets.