Abstract: In order to search for the potential value of microbial polysaccharide in formulation processing,the functions of Paenibacillus polymyxa polysaccharide crude extract in microbial pesticide were researched with investigation of suspensibility improvement (for pesticide carrier),heat protection and UV protection of P.polymyxa polysaccharide. Results showed that P.polymyxa polysaccharide could improve the carrier suspensibility of diatomite,kaolin and calcium carbonate.When each 1 g of the above three carriers was added 0.25 g polysaccharide crude extract,their suspensibility were increased by 62.6% ,161.8% and 284.0% ,respectively.Additionally, P.polymyxa polysaccharide showed obvious heat protection for HY96-2 endospores,and obvious ultraviolet (UV) protection for vegetative cells and endospores of both P.polymyxa HY96-2 and Bacillus marinus B-9987.When HY96-2 endospore suspensions were heated at 80 ℃ for 20 min,survival ratio of HY96-2 endospores with 0.5% (W∶V) polysaccharide addition was increased by 31.0% at the basis of control.When 0.5% (W∶V) polysaccharide crude extracts were added,survival ratios of HY96-2 vegetative cells and endospores irradiated by UV-B (290-320 nm)for 6 hours were increased by 14.1% and 22.6% compared with the controls,respectively;and survival ratios of vegetative cells and endospores of B-9987 were increased by 36.4% and 29.5% compared with the controls.The polysaccharide extract could be applied as adjuvant in P.polymyxa wettable powder processing progress,taking the place of chemical adjutants.