The renewable energy consultancy said it would work with GEDI to help design wind turbine foundations and evaluate suitability for different projects. It said it would provide technical support and design, and issue technical reviews for each project.
Mingyang is one of the suppliers seeking to install its turbine at the project.
Speaking about the deal, Mathias Steck, GL Garrad Hassan regional manager for Asia, said: "Guangdong province is set to become an important provider of clean and reliable energy through the start of the offshore wind development.
"China's wind industry is progressing with unprecedented speed and momentum across all aspects of the wind energy generation chain. We are proud to contribute to this success by supporting GEDI and delivering wind turbine designs and measurement campaigns, offshore training and consultancy, strategic advice, inspection and quality assurance."
In June, GEDI announced a deal with UK consultancy Sgurr Energy to advise on its 198MW Zhuhai wind project, scheduled for connection to the grid in late 2014.
Sgurr is to advise on site selection, design and layout, plus ocean hydrometeorology and will conduct an environmental impact assessment.