Abstract: The invention relates to a method for the flow synthesis manufacture of RDX, comprising the steps of preparing input flow reagent A, comprising hexamine dissolved in nitric acid with a concentration less than 92%, preparing input flow reagent B comprising 99% concentration nitric acid, causing the input flow reagents A and B to enter a flow reactor at a flow rate, so as to cause a total nitric acid concentration of greater than 93%, in said flow reactor, cooling the reaction chamber to less than 30° C., causing the output mixed flow to be quenched.