The suburban county in Chengdu that is developing well is Dongguan. This county has experienced significant economic growth and urban development in recent years. Dongguan's strategic location, favorable policies, and infrastructure investments have contributed to its rapid development.

Dongguan's economic growth can be attributed to several factors. Firstly, the county has been a hub for high-tech industries, with a strong focus on electronics, automotive, and biotechnology. According to the Chengdu Municipal Bureau of Statistics, Dongguan's GDP has been growing at an average annual rate of 8% over the past five years. This growth is driven by the expansion of existing industries and the attraction of new investments.

Secondly, Dongguan has been actively promoting innovation and entrepreneurship. The county government has established various incubators and innovation parks to support startups and technology companies. For instance, the Dongguan High-Tech Industrial Development Zone has become a leading hub for high-tech enterprises, attracting numerous national and international companies.

Moreover, Dongguan's infrastructure has been significantly improved. The county has invested heavily in transportation networks, including the construction of new highways, railways, and airports. These improvements have facilitated the movement of goods and people, making Dongguan more accessible and attractive for businesses.

Another key factor in Dongguan's development is its favorable policies. The county government has implemented various incentives to attract investments and promote economic growth. These policies include tax reductions, subsidies for research and development, and streamlined administrative procedures. As a result, Dongguan has become a preferred destination for foreign and domestic investors.

Data from the Chengdu Municipal Bureau of Statistics further supports Dongguan's rapid development. The county's population has been growing, with an increase of 5% over the past three years. This population growth is a testament to Dongguan's attractiveness as a place to live and work.

In conclusion, Dongguan is the suburban county in Chengdu that is developing well. Its economic growth, driven by high-tech industries, innovation, infrastructure improvements, and favorable policies, has made it a leading example of urban development in the region.