【Objective】 To evaluate the effect of modified bagasse (MSB, MSB-Mo and MSB-CI) on the immobilization of mesotrione-degrading bacteria strain HZ-2.【Method】Three types of modified bagasse and activated carbon were selected as the carrier candidates for the bacterial immobilization，and the degradation abilities of immobilized composites were examined.【Result】After 48 hours culture, the high D_{600 nm} values indicated that modified bagasse(MSB, MSB-Mo and MSB-CI) and activated carbon had strong abilities to immobilize bacteria. More than 85% of mesotrione in LB medium was degraded using modified bagasse as a carrier after 3 days of culture, which was higher than the results of activated carbon. MSB-Mo composite had the best degradation performance with a degradation rate of 96.35%.Moreover,mesotrione in soil was degraded over 99% after 7 days by adding glucose as support nutrient to the modified bagasse. 【Conclusion】 Modified bagassse MSB-Mo is the most available carrier material, which demonstrates the highest potential of being a new biological carrier material for immobilization of mesotrione-degrading bacteria strain.