Abstract: The contents of free amino acids in the haemolymph of Anoplophora glabripennis larvae infected with Metarhizium anisopliae were measured by HPLC (High Performance Liquid Chromatograph).The results showed that there are 17 kinds of free amino acids in the haemolymph of A.glabripennis larvae.During different post-infection periods,the total contents of free amino acids fell first and rose later.After infection by M.anisopliae,the total contents of free amino acids in the haemolymph of A.glabripennis larvae decreased in a small scale compared with that of the control from 24 to 72 hours.The contents fluctuated but the difference was not marked at the 3 time points of measurement.The contents decreased significantly from after 72 hours up to 120 hours and reached the lowest value (1042.33 mg/100 mL) at 120 hours post-infection.Afterwards the contents increased sharply.The total contents at 144 hours and 168 hours were 1.44 and 1.51-fold of that at 120 hours, respectively.The trends of changes of the contents of free amino acids,Lys,Val,Phe,Arg,Tyr,Thr, Ile,His,Leu,Ala,Gly and Met,were similar as that of the total.Meanwhile the contents of the free amino acids,Pro,Ser,Glu,Asp and Cys,fluctuated.