The human VEGF₁₂₁ cDNA was amplified by RT-PCR, and was inserted into the Pichia pastoris expression vector pPIC9K to form the expression plasmid p9KVEGF₁₂₁. This recombinant plasmid was transformed into GS115. Transformants were screened by G418-YPD plates and were induced by methanol. The expression product of r-hVEGF₁₂₁ amounted to 900 mg/L by a 5-liter fermentor, over 70% of the total secreted protein. The purified r-hVEGF₁₂₁ can stimulate the proliferation of bovine capillary endothelial cells and shows high vascular permeability.