For the life expectancy of diffuse large B-cell lymphoma, with its stage, chemotherapy or not and other factors, the general 2-year survival rate is around 44% to 87%, and the 5-year survival rate is around 26% to 73%. For the life expectancy of diffuse large B-cell lymphoma is mainly based on the International Prognostic Index (IPI) to determine its 2-year survival rate and 5-year survival rate. The 5 poor prognostic IPIs include age greater than 60 years, staging at stage III or IV with more than 1 extranodal lesion, being bedridden or living in the care of others, and elevated serum LDH. The prognosis of diffuse large B-cell lymphoma can be determined based on the number of IPIs the case has. Based on the IPI art can be categorized as low-risk, low-intermediate-risk, high-intermediate-risk, and high-risk. The 2-year survival rate and 5-year survival rate for low-risk IPI number of 0 to 1 were 84% and 73%, respectively. The number of low-intermediate-risk IPIs was 2, and its 2-year survival rate and 5-year survival rate were 66% and 54%, respectively. The number of high intermediate-risk IPIs was 3, and their 2-year and 5-year survival rates were 54% and 43%, respectively. The number of high-risk IPIs was 4-5, and the 2-year and 5-year survival rates were 34% and 26%, respectively. Therefore, when the diagnosis of diffuse large B-cell lymphoma is confirmed, one should go to the earliest regular hospital and be treated accordingly under the guidance of the doctor.