Lactate dehydrogenase (LDHA) activation induces tumorigenesis by activating tumor proliferation, growth, invasion, and metastasis. Whether LDHA mediates tumor metabolism that upon diffuse large B-cell lymphoma (DLBCL) occur remains unknown. Here, we investigated how LDHA adopt tumor metabolism after activation to regulate DLBCL-inducible. We investigated LDHA is highly expressed in peripheral blood mononuclear cells (PBMCs) of DLBCL patients. Knockdown of LDHA results in an increase in the apoptosis of cells, suppression of cell growth and migration in OCI-Ly1 and OCI-Ly10 cells. We show that LDHA gains a canonical enzyme activity to produce lactate and triggers NAD + in DLBCL cells. Furthermore, p-STAT5 was identified as a downstream target of LDHA, and the p-STAT5 protein level was significantly reduced related to decreased LDHA protein expression. Collectively, our findings identify the oncogenic role of LDHA in DLBCL and suggest that LDHA can be considered as a pivotal prognostic biomarker and a potential therapeutic target.