Abstract: The present invention relates to method and apparatus for asyncyhronous motor's speed regulation using strobe control, which may be carried out graded or nongraded speed regulation in conventional monospeed squirrel cage motor with simplicity, reliability, cheapness and high efficiency. It provides a notable electricity-saving result with good economical efficiency, especially in asynchronous motors speed regulation of ventillator and water pump driving. The said speed regulation method is using switch 5,6 sequentially to transmit a positive half-wave voltage and a negative half-wave voltage between the input terminals of strating and working windings of asynchronous motor 1, and then, will be repeated above said cycle continuously.