Abstract: Peripheral T-cell lymphoma (PTCL) is a type of malignant lymphoma that is derived from different stages of T-cell carcinogenesis in the posterior thymus and has obvious heterogeneity in biological behavior and clinical manifestations. Diagnosis of PTCL is mostly during late stage and progresses rapidly. Even with high-intensity treatment, the cure rate is still low. Extranodal NK/T cell lymphoma (ENKTL) is defined as NK/T cell lymphoma that originates in the nasal cavity or other extranodal organs. ENKTL is a rare and special type with highly relative incidence in Asian populations, accounting for about 5%-15% of NHL. ENKTCL has a high degree of malignancy, rapid clinical progress, and poor prognosis. In order to seek more standardized diagnosis and treatment guidance, it is particularly important to learn and understand authoritative guidelines international and domestic. In this passage, we will interpret clinical guidelines such as the Chinese Society of Clinical Oncology (CSCO) lymphoma guidelines and the National Comprehensive Cancer Network (NCCN) guidelines, focusing on the changes in the PTCL and NKTCL guidelines in the past two years (2019-2020).