China remains a top investment destination for U.S. companies in 2010 amid the global economic slowdown as they expect to see continuous growth in sales and profit, an American Chamber of Commerce (AmCham) study showed.

More than 90 percent of respondents had an optimistic business outlook on China based on an AmCham survey of 369 American companies, up from 80.7 percent in a similar survey in 2008, AmCham said a research report, released on Wednesday.

The study also found that 64.5 percent of those surveyed had plans to increase their investment in China next year, up from 58.6 percent in 2009.

American companies are finding that their performance in China is the bright spot in an otherwise difficult global picture, J. Norwell Coquillard, chairman of AmCham Shanghai, said in a statement.

China has been a major growth engine this year amid the global economic downturn thanks to the government's 4 trillion yuan ($586 billion) stimulus package, which has effectively steered the economy back to a healthy growth path.

As such, many U.S. companies, hit badly at home, are increasingly turning to China for growth.

Fifty-nine percent of U.S. companies surveyed are producing goods and services for the China market this year, up sharply from 39 percent last year, the largest increase since 2006.

Those in China who primarily export to their home market dropped to 16 percent in 2009 from 21 percent in 2008, the survey showed.

However, China, on track to meet its economic growth target of 8 percent this year, is not immune to the global downturn.

The number of respondents who expected a year-on-year rise in revenue in 2009 dropped to 47 percent from 77 percent in 2008, while those expecting flat earnings or a fall in profit came to 36 percent, the steepest rise since 2002, it said.

($1=6.827 Yuan)

(Reporting by Fang Yan and Jacqueline Wong)