In recent years, more and more powerful molecular/cellular biological techniques of intraocular fluid have made ophthalmologists tend to only rely on these methods in the diagnosis of intraocular lymphoma because of their features of simplicity, fastness and efficiency. The molecular/cellular biological techniques of intraocular fluid cannot be used as the basis for the diagnosis of intraocular lymphoma because it can only indicate the existence of tumor cells indirectly. Intraocular tissue/cell pathology remains the gold standard for the diagnosis of intraocular lymphoma, and its importance cannot be replaced by any other molecular/cell biological methods. Understanding and mastering the advantages and limitations of various diagnostic techniques, standardizing and optimizing the collection, preservation and submission process of intraocular tissue/cell specimens will help ophthalmologists improve the diagnostic efficiency and medical quality of intraocular lymphoma.