The invention provides a high-voltage pulse modulation power supply based on grouping alternative triggering, which comprises a direct-current voltage-stabilizing power supply, a plurality of solid switches, a plurality of triggers and a sequence control module, wherein the direct-current voltage-stabilizing power supply is used for supplying power for the high-voltage pulse modulation power supply; the triggers correspond to the solid switches, wherein each trigger provides a trigger signal for the corresponding solid switch to conduct the corresponding solid switch, the triggers are divided into at least two groups of triggers; and the sequence control module controls the triggers to generate trigger signals at moments of t1 so as to conduct the solid switches simultaneously, and controls one group of the at least two groups of triggers to generate triggers signals at moments of t2 so as to conduct the solid switches corresponding to the group of triggers, wherein the moments of t1 and the moments of t2 alternatively occur.