The $169.5 million solar power station that has a generating capacity of 20 megawatts will be the world's largest solar power plant, Dongyang said in a statement.
"This will correspond to the annual power consumption of more than 6,000 households," it said. Germany's Bavaria solar plant is the largest with an 11 MW capacity.
The project is part of South Korea's plan to develop clean and renewable energy resources to reduce consumption of fossil fuel.
South Korea is the world's fourth-largest oil importer and second-largest gas buyer, and imports almost all of its crude oil requirements.