Abstract: Radioimmunotherapy is a major component of radionuclide therapy and always being the main field of re-search.Zevalin^TM is the first FDA marketing approved radioimmunotherapy agent which is indicated for the treatment of relapsed or refractory low grade non-Hodgkin's lymphoma.In this review,the component,therapeutic regimen,pharmacological mechanism,radiation dosage and clinical experiment result of Zevalin^TM are described respectively.