The invention discloses a method and a system for DDS (direct digital synthesizer) pulse edge adjusting and a pulse signal generator. The pulse signal generator comprises input equipment, a microprocessor, a DDS module and a digital-analog converter in sequential connection, the DDS module comprises a phase accumulator, an amplitude converting module, a pulse-width adjusting module and an edge adjusting module, the edge adjusting module comprises a detection module, a rising edge adjusting module and a falling edge adjusting module, the detection module is used for detecting arrival time of a rising edge and arrival time of a falling edge of initial pulse signal data, the rising edge adjusting module is used for realizing rising edge adjusting of the initial pulse signal data according to an upper stepping value, and the falling edge adjusting module is used for realizing falling edge adjusting of the initial pulse signal data according to a lower stepping value. Compared with the prior art, by the technical scheme, quick rising and falling of pulse signal edges can be realized when frequency is low, the duty ratio is extremely low, and large-scale accurate pulse signal edge adjusting can also be realized.