The invention relates to a preparation method of a novel anti-infective 
drug. The preparation method comprises the following steps: (1) salifying, namely putting cefazedone and a 
sodium acetate 
solvent in absolute 
methanol to have a salifying reaction, and controlling the temperature in the range of 10-30 DEG C after the cefazedone is completely dissolved, (2) decoloring, namely adding 
active carbon to a reaction liquid, stirring and decoloring, and removing the 
active carbon by filtering, keeping the temperature of the filtrate in the range of 10-30 DEG C, and then re-filtering; (3) crystalizing, namely slowly and dropwise adding a certain amount of 
ethanol to the filtered filtrate at a rate of 20L / H under a stirring condition until the 
system is turbid, growing crystals for 0.5 to 1 hour, next, adding a certain amount of 
acetone, growing crystals for 0.5 to 1 hour, and then reducing the temperature to 5 DEG C at a temperature reducing rate of 5-15 DEG C per hour, and stirring by keeping the stirring speed in the range of 80-120r / min for 
crystallization, and growing the crystals for 1-3 hours; and (4) 
drying, namely filtering and washing the 
filter cake, and 
drying to obtain refined 
cefazedone sodium. Compared with the prior art, the preparation method is simple to operate, low in cost and high in yield, and 
pollution is greatly reduced; and the obtained refined 
cefazedone sodium is low in 
moisture content, low in 
impurity content and high in stability.