Abstract： Objective To determine the relationship between the serum level of β2-microglobin (β2-MG)and international prognostic index (IPI) and investigate the role of IPI in predicting the prognosis and making individualized therapy for peripheral T-cell lymphoma (PTCL).Methods Eighty-one patients with PTCL were treated by standard CHOP regimen.The clinical characteristics,response,long-term surival rates and the relationship between serum level of β2-MG and IPI scores were analyzed retrospectively.Results Eighty-one patients were eligible.All of them were treated by CHOP regimen.The overall response rate (RR) was 82.7 ％ with 53.1％ complete remission (CR) rate.The RR of IPI low risk,low-intermediate risk,high-intermediate risk,and high risk were 95.7 ％,87.5 ％,53.8 ％ and 20.0 ％,with CR rate 74.5 ％,37.5 ％,15.4 ％ and 0,respectively (P ＜0.05).The median survival times (MST) were 31.2 months at a median follow-up of 30 months (2-98 months).The acturial 1-,3-,and 5-year overall survival (OS) rates were 83.5 ％,41.8 ％ and 34.7 ％,respectively.The 5-year OS rates of low risk,low-intermediate risk,high-intermediate risk,high risk were 57.3 ％,55.9 ％,0 and 0,respectively (P ＜0.05).The OS rates of low risk group (IPI 0-2 scores) and high risk group (IPI 3-5 scores) were 54.8 ％ and 0,respectively (P ＜0.05).Serum levels of β2-MG were significantly elevated in the high risk group than those in the low risk group.The proportion of abnormal serum level of [β2-MG were also significantly elevated in the high risk group than those in the low risk group.The results of multivariante analysis showed that serum level of β2-MG and IPI scores were independent prognostic factors for PTCL (P＜0.05).Conclusion The serum level of β2-MG with IPI scores system can be uscd for evaluating the prognosis of PTCL patients.