Cefradine is the first generation of cephalosporins, which is used in the treatment of urinary and respiratory infection and is one of the most often used antibiotic. The influnces of pH value of dissolved liquid and crystallization end point,humidity,temperature and illumination five factors on the stability of cefradine were studied dissolved liquid initial pH value is 2.1, pH value of crystallization end point is low, storage temperature and humidity is low, the stability of cefradine is higher thereby easy to store.The research has a very important role in improving the stability of cefradine and further expanding its application.