Abstract: With different pulsed magnetic field processing, the effect of magnetic field on the survival and growth of Monochamus alternatus larva were observed. After the magnetic field processing, the dynamic change of the larva of M. alternatus with regard to the activity, growth, membrane permeability and cellulosic enzyme activity were discussed. The results showed that: (1)After treated with pulsed magnetic field, the larva of M. alternatus could be killed to some extent and pulse rise time was the main factor that influenced the survival of M. alternatus. When 5ms (magnetic peak 3180Gs) pulse rise time treated the M. alternatus larva, the average corrected mortality could reach to 63%. The greater the pulse rise time, the higher corrected mortality of M. alternatus larva would be. (2)When subjected to pulsed magnetic field, the larva of M. alternatus would become deformed such that it could not pupate as usual; it would suffer diapause phenomenon and could not enter next life cycle normally or the average time needed to pupate increased. (3)Pulsed magnetic field could destroy the cell membrane structure of the larva of M. alternatus, causing a part of electrolyte in the cell to leak out. The effect of the pulsed magnetic field on the membrane permeability of M. alternatus was assessed with relative conductivity and it was found that pulse rise time was the main impact factor, the greater the pulse rise time, the higher relative conductivity of M. alternatus larva would be. (4)After the treatment of pulsed magnetic field, the cellulosic enzyme activity of M. alternatus larva would be degraded and the greater the pulse rise time and the more the pulse train number, the lower the cellulosic enzyme activity would be, with C1 enzyme activity lowered most.