Abstract: The effects of protective agent， preservation method and rejuvenation method on Paenibacillus polymyxa C12's survival rate and production ability were studied. The results were as following， using 20% skimmed milk powder as protective agent， the survival rate of the strains in -80℃ preservation was 17.3 times higher than the freeze-drying preservation; In the -80℃ preservation， adding thehalose and dimethyl sulfoxde into 20% skimmed milk， the average relative antibiotic titer increased by 4.5% and 4.1%， respectively; In the freeze-drying preservation， adding thehalose into 20% skimmed milk the average antibiotic production increased by 6.0%， and the survival rate increased by 5 times; The strains preserved in -80℃ for six months， then separated and purified for three times，the highest antibiotic production capacity returned to 93%， and the average antibiotic production capacity returned to 80%; Using resistance plate to separate and purify for one time， the highest antibiotic production capacity returned to 81%， and the average antibiotic production capacity returned to 45%.

Key words: Paenibacillus polymyxa, polymyxin E, preservation, rejuvenation