As one of the most prosperous countries in the world, Saudi Arabia has a significant number of commercial interests on the mainland.
And Hong Kong, as one of Asia's prime economic hubs, is also involved.
Oil is the most obvious trading entity. Saudi Arabia holds a quarter of the earth's proven oil reserves, is the world's largest exporter of petroleum, and plays a leading role in Opec, a cartel of oil-producing countries.
This makes the kingdom a good match for the mainland, which has a huge appetite for oil, exacerbated by its burgeoning economic growth.
The two countries initially set a target of trade volume at US$40 billion for this year. However, this was reached early, in 2008. Now, forecasters are predicting that a goal of US$60 billion could be achieved before 2015.
Trade has shown rapid growth over the past decade.