(1) add Urethylane at sodium hydroxide solution, then drip aqueous hydroxylamine, after dropwising, carry out condensation reaction;
(2) react rear hydrochloric acid and adjust pH7-8; Suction filtration while hot after 58 ~ 62 DEG C of underpressure distillation go out the water of 70 ~ 80% afterwards; Then holding temperature 58 ~ 62 DEG C, joins filtrate in resin cation (R.C.) and decolours;
(3), after decolouring, suction filtration is carried out; Then when filtrate is cooled to 0 ~ 5 DEG C, insulation crystallization; And then carry out suction filtration, filter cake 0-5 DEG C of cold water washing twice; With the use gauge of azanol, the consumption washing material water for the 1st time is 0.8 ~ 1.0ml/g, and the consumption washing material water for the 2nd time is 0.6 ~ 0.8ml/g; Hydroxycarbamide product is obtained finally by drying.