The carrier will purchase 30 Next-Generation 737 and 50 737 MAX planes valued at USD 7.24 billion at list prices, it said in a statement to the Shanghai stock exchange.
The company's Xiamen Airlines unit will buy an additional 30 737 MAX models valued at USD 2.88, it said in a separate statement.
China, the world's second-largest economy, is already Asia's biggest aircraft buyer as a growing middle class takes to the skies in ever-increasing numbers.
The major Boeing order comes despite slowing growth in the Chinese economy, which aviation industry officials fear could hurt air travel.
China logged its worst economic performance since the global financial crisis in the third quarter, with gross domestic product rising just 6.9 per cent -- its lowest level in six years.
Seattle-based Boeing has estimated that China will add 6,330 new aircraft worth USD 950 billion to its commercial fleet by 2034.