The invention relates to a dodecagon space voltage vector control soft starter and a control method thereof. The dodecagon space voltage vector control soft starter is powered by a three-phase alternating current power source; four full-control devices and eighteen diodes form a dodecagon space voltage vector control circuit under the control of a microcontroller; the rotating frequency of a stator magnetic field of an asynchronous motor can be controlled through the above components; after each voltage cycle dodecagon moves i steps continuously, wherein i can be 1,2,3,4,5 and 6, and then moves i steps after passing one each voltage cycle until moves a complete dodecagon space voltage vector, and then 12/i frequency division is performed on a 50Hz power source, and the frequency of the power source is 50*i/12 (Hz); and finally, the frequency of the rotation of the stator magnetic field is increased by 50/12Hz = 4.167Hz every time from 4.17Hz until the frequency of the rotation of the stator magnetic field is increased to 25Hz, and then voltage regulation and speed regulation are performed, namely, the frequency of the rotation of the stator magnetic field achieves 50Hz,and therefore, normal starting of the motor under small current can be ensured.