The utility model discloses an on -load voltage -regulating transformer's pressure regulating controlling means, include: on -load voltage -regulating transformer for insert the outside communication electricity, grid voltage to external load is joined in marriage in output after the vary voltage, the pressure regulating controlling means include: power adaptation module, microcontroller, voltage sample module, the variable voltage electric drive device includes: step motor, gear units, rack, power adaptation module inserts external power source for change external power source's voltage, provide the power, the voltage sample module inserts joins in marriage grid voltage for join in marriage grid voltage to this and sample, generate sampled signal and send to microcontroller, microcontroller connects step motor for receive sampled signal, the control stepper motor rotates, step motor makes gear units rotate through rotating, the rack meshes with gear units mutually, makes rack linear motion by gear units's rotation, fixedly on the rack setting up adjustable transformer tap, can remove along with the rack, adjusts on -load voltage -regulating transformer's transformation ratio.