Abstract: Objective To investigate the expression, significance of YAP1 and P53 protein in B cell non-Hodgkin's lymphoma(B-NHL) and the relationship between these two indicators. Methods Tissue microarray and immunohistochemistry were used to detect the expression of YAP1 and P53 protein in 60 cases of B-NHL (case group) and 25 cases of reactive lymphoid hyperplasia(control group) which were pathologically confirmed in the First Affiliated Hospital of Guangzhou Medical University from January 2012 to December 2017. B-NHL were further categorized into DLBCL group (49 cases) and indolent B-NHL group (7 cases of SLL and 4 cases of MCL). Results The overall positive rate of YAP1 in B-NHL was 68.3%, and it was 61.2% in diffuse large B cell lymphoma (DLBCL), 100% in indolent B-NHL group and control group, respectively. The positive rate of YAP1 protein in DLBCL was lower than that in the indolent B-NHL group and control group, and the difference was statistically significant (all P＜ 0.05).The overall positive rate of P53 in B-NHL was 16.7%, and 18.4% in diffuse large B cell lymphoma (DLBCL), 9.1% in indolent group, negative in control group, respectively. There was significant difference in the expression of P53 protein in B-NHL and control group (P＜ 0.05). There was no significant correlation between YAP1 and P53 expression in B-NHL (P＞ 0.05). Conclusion YAP1 may be involved in the occurrence and development of some B-NHL as tumor suppressor genes, and its expression is unrelated to P53 overexpression.