Retinopathy of prematurity (ROP) has become one of the leading causes of blindness and visual loss in children over the last half century. Vascular Endothelial growth Factor (VEGF-A) is the principal stimulator of angiogenesis. Recently, it has been identified that VEGF was differentially spliced from Exons 8 to Exons 8a and 8b to form two families: the pro-angiogenic VEGFxxx family and the anti-angiogenic VEGFxxxb family. This alternate splicing produced VEGFxxxb proteins of the same length as VEGFxxx family, but with different C terminal amino acid sequences. VEGFxxxb appeared to be able to inhibit VEGFxxx-dependent angiogenesis. In our study, we investigated the protein and mRNA expression course of VEGFxxx and VEGFxxxb by Western-blot and RT-PCR in a mouse model of Oxygen-induced Retinopathy (OIR) from postnatal day 1 (P1) to postnatal day 21 (P21). We also analyzed the ratio of VEGF165b versus total VEGF165 isoforms protein expression in the OIR mouse model. We found that both VEGFxxx and VEGFxxxb were present in the mouse retina, among which, VEGF165 and VEGF165b appeared to be predominant VEGFxxx and VEGFxxxb isoforms respectively in the mouse retina. VEGF165b and total VEGF165 isoforms had different expression pattern correlated with neovascularization development. In OIR group, the protein level of total VEGF165 isoforms continuously increased and peaked at P17 while VEGF165b continuously decreased from P9. Similarly, the mRNA level of VEGFxxx elevated early and peaked at P17 While VEGFxxxb decreased from P9. Therefore, increasing the concentration of VEGFxxxb isoforms or inhibit the pro-angiogenic VEGFxxx isoforms may be a more effective therapeutic strategy for ROP.