China's major oil company, Sinopec, has topped an annual ranking of the biggest-earning Chinese enterprises for the eighth straight year, showed the latest results.

The 2012 China Top 500 Enterprises List was published by the China Enterprise Confederation and the China Enterprise Directors Association on Saturday.

Sinopec, with 2.55 trillion yuan ($402 billion) revenue in 2011, was followed in second place by another oil company, China National Petroleum Corporation, which also reported a revenue over 2 trillion yuan.

The two were joined by eight other big state firms in the top 10 -- State Grid; Industrial and Commercial Bank of China; China Construction Bank; China Mobile; Agricultural Bank of China; Bank of China; China State Construction; and China National Offshore Oil Corporation.

All of the companies that made it onto the list should report an annual revenue higher than 17.5 billion yuan. Of them, 107 reported a revenue over 100 billion yuan, including 15 private enterprises, according to the list. In the 2011 version, only six private enterprises reported more than 100 billion yuan in revenue.

The 500 companies had a combined revenue of 44.9 trillion yuan in 2011, up 23.6 percent from a year earlier. But the profit-revenue ratio declined 1.07 percentage points to 4.7 percent, reflecting that the companies failed to maintain high profit growth in the current complex economic situation.