Nano powder preparation method and reactor

The invention relates to a preparing method of nanometer powder and a reactor of nanometer powder. The inventive reactor of nanometer powder comprises a cabin which contains a micro-emulsification region and a reaction region; an inner baffle board for dividing the micro-emulsification region into several secondary regions; at least one porous element mounted on the inner baffle board; a first material inlet for transferring the first solution to one secondary region; a second material inlet for transferring the second solution to another secondary region; and a third material inlet for transferring the third solution to another secondary region. Said inner baffle board can rotate around one rotation shaft to generate hyper-gravity at the radial direction of reactor, while filled solution can move from the center of reactor to the outer diameter. Said porous element can individually mix the first solution, second solution and third solution to form the first micro-emulsion cell and second micro-emulsion cell which can react in the reaction region to prepare said nanometer powder.