Production method of analgin bulk drug

The invention discloses a production method of analgin bulk drug and belongs to the pharmceutic field. The production method particularly comprises the following steps: step 1: antipyrine is taken as a raw material, and 4-amino-antipyrine oil is obtained through nitrosification, reduction, hydrolyzation and neutralization reaction; step 2, formylation is performed on 4-amino-antipyrine so as to obtain 4-formylaminoantipyrine; step 3: 4-dimethylaminoantipyrine is prepared through methylation, hydrolyzation, and neutralization reaction of 4-formylaminoantipyrine; step 4: 4-formylaminoantipyrine is prepared to be analgin solution through condensation reaction; step 5: the analgin solution obtained from the step 4 is refined and crystallized, and finally, analgin is prepared. In the invention, by improving the conventional manufacturing technique, the purity of analgin product is improved, contains of other unknown impurities are reduced, the colourimetric number is lower and the crystallization color is whiter.