To understand P53 gene change of non-Hodgkin's lymphoma (NHL) and human malignant lymphoma cell lines, the exons 5-7 of 29 patients with NHL and 9 kinds of human malignant lymphoma cell lines were studied by silver staining PCR-SSCP technique. Three cases of P53 gene point mutation was found in 29 cases of NHL. Mutation developed in exon 5 in 2 cases, and in exon 6 in 1 case. They were all diffuse lymphoma. In mutation cases, B-cell lymphoma accounted for 2 cases and the other one was T-cell lymphoma. There was no P53 gene mutation in low-grade follicular lymphoma. Seven strains out of 9 kinds of lymphoma cell lines had P53 gene point mutation. One strain had the mutation in exon 5; 5 strains in exon 6 and 1 strain in exons 5, 6, 7. There was a high mutation rate in lymphoma cell lines and low mutation rate in NHL patients. P53 gene plays an important role in lymphoma cell line establishment, cell regeneration and disease evolution.