The invention provides testing equipment and method of moment of inertia of moving parts of a diesel generating set. The equipment comprises a speed signal sorting module, a keyboard input module, a computing control module and a display module, wherein the input end of the speed signal sorting module is connected with a speed sensor of a motor and the output end thereof is connected with a pulsecounting interface of the computing control module; the output end of the keyboard input module is connected with P1.0-P1.6 pins of the computing control module; the input quantity of the computing control module is the speed pulse signal output by the speed signal sorting module and the keyboard instruction signal of the keyboard input unit; the output quantity signal of the computing control module is the control instruction of the display module; and the data line of the display module is connected with the P0 port of the computing control module. The moment of inertia of the set is computed by utilizing the speed change data or curve tested in the specific time slot in the speed regulation characteristic test of the diesel generating set. The invention is applicable to determining themoment of inertia of the movement system of the diesel generating set.