Objective To investigate the effect of PTEN induced kinase (PINK1) on CD20 expression in diffuse large B cell lymphoma (DLBCL) through phosphorylation of histone deacetylase 3 (HDAC3).Methods DLBCL cell line oci-ly7 was collected and randomly divided into control group, sh-pink1 group and sh CON group. The expression levels of PINK1, CD20 mRNA, HDAC3, p-hdac3 ser424 protein in each group were compared. The expression levels of PINK1, p-hdac3, ser424 and CD20 in cytoplasm and nucleus of sh-pink1 group and sh CON group were compared. The remaining oci-ly7 cell lines were randomly divided into DMSO group, rgfp966 group and con group. The cells in rgfp966 group were treated with 10 μ m HDAC3 specific inhibitor rgfp966 for 24 hours, and DMSO group cells were used as inhibitor control. The expression levels of CD20 protein in each group were compared. Results The expression levels of PINK1 mRNA and protein in sh-pink1 group were significantly lower than those in control group, while the expression levels of CD20 mRNA and protein in sh-pink1 group were significantly higher than those in control group (P＜0.05). There was no significant difference in PINK1, CD20 mRNA and protein expression between SH CON group and control group (P＞0.05). The expression of p-hdac3 ser424 protein in sh-pink1 group was significantly lower than that in control group (P＜0.05). There was no significant difference in p-hdac3 ser424 protein expression between SH CON group and control group (P＞0.05). In the nucleus, the protein expression levels of PINK1 and p-hdac3 ser424 in sh-pink1 group were significantly lower than those in control group (P＜0.05). In cytoplasm, the expression of CD20 protein in sh-pink1 group was significantly higher than that in control group (P＜0.05). The expression of CD20 protein in oci-ly7 cells in rgfp966 group was significantly higher than that in con group (P＜0.05). There was no significant difference in CD20 protein expression between CON group and DMSO group (P＞0.05).Conclusion in diffuse large B-cell lymphoma, PINK1 can phosphorylate ser424 site of HDAC3, activate HDAC3, and finally achieve transcriptional inhibition of CD20 expression. Knockdown of PINK1 expression or blocking of HDAC3 expression can significantly promote CD20 expression.