AIM: To investigate the effect of HtrA1 on the proliferation, migration and apoptosis of human retinal pigment epithelium (RPE) cells in the light injured model, as well as the expression of the apoptosis related molecules. METHODS: The human RPE cell line ARPE-19 was exposed to blue light to establish the light injured model. The cells were transfected with HtrA1 siRNA to knockdown HtrA1 expression. Subsequent expression of HtrA1 was determined by real-time polymerase chain reaction (RT-PCR) and Western blot, respectively. Changes in cell proliferation, migration and apoptosis were assessed by cell counting kit-8 (CCK-8), Transwell assay and flow cytometry respectively, as well as changes in the mRNA and protein levels of Bax, Caspase-3 and Bcl-2 expression. RESULTS: HtrA1 was highly expressed in ARPE-19 cells after blue light irradiation. Knockdown of HtrA1 expression inhibited the proliferation, migration and apoptosis of the blue-light-irradiated ARPE-19 cells (P<0.05). Bax and Caspase-3 expression were significantly reduced both at mRNA and protein levels (P<0.05) after siRNA treatment. Bcl-2 expression significantly increased in blue-light-irradiated ARPE-19 cells after siRNA interference (P<0.05). CONCLUSION: Silence of HtrA1 may inhibit the proliferation, migration and apoptosis of ARPE-19 cells in light injured model. Moreover, HtrA1 suppression in blue-light-irradiated ARPE-19 cells may ameliorate cell apoptosis through down-regulation of Bax and Caspase-3, and up-regulation of Bcl-2 expression.