Abstract: In this paper,the effect of temperature on Paecilomyces lilacinus growth was investigated.The growth index for OD,pH,mycelia dry weight,and spore number and their toxic effect on nematodes at different temperatures (15～35℃）were analyzed.Results show that temperature is a key factor of fermentation.Paecilomyces lilacinus exhibits normal growth within 20～30℃，optimum mycelia growth and sporulation occur at 25℃,mycelia biomass reaches 1.08g in 9 days,spore number reaches 4.012×10⁶/mL in 10 days.Between 15～30℃，higher temperatures can increase C and N consumption and toxin production.At 30℃,cultured 7d,the toxicity to Ditylenchus destructor can reach 64.60%.