At the juncture of Dayawan and Honghaiwan of China South Sea, Huidong Harbour Nature Reserve lies along the gulf shores at the foot of the Dashan Mountain, covering an area of 1400 hectares locally known as "Gulf of Sea Turtle". In 1992 the Reserve was set up to preserve the precious ocean reptile under key state protection.

At this typical tropical sea area, the average annual precipitation measures 1402 to 2085 mm, the average temperature is 22°to 28°C in summer and autumn.

In June to September the female turtle digs a large pit about 2 m across and 1 m deep, throwing up sand with all four limbs; having done this. she excavates a smaller flask — shaped egg chamber with the hind limbs. This is done with appreciable skill for an animal so generally unsuited to terrestrial locomotion. About 50 to 200 eggs are laid in the chamber which the female then covers over with sweeps of her hind limbs. She then refills the whole pit with her front limbs. finally wandering over the site thrash the sand to obscure the exact nest location.

In China, the green sea turtle's native haunt extends from Guangxi to south Shandong, but 90 percent of its breeding grounds are found in islands and coastal areas of China South Sea.