BEIJING—Nearly four-dozen U.S. business and professional groups have signed a letter to the Chinese government urging it modify a draft law that seeks to tighten controls on foreign nongovernmental groups, saying that it could hurt U.S-China relations.

The letter, reviewed by The Wall Street Journal, was signed by 45 groups representing industries ranging from technology to agriculture to entertainment. They include the American Apparel and Footwear Association, the American Petroleum Institute, BSA The Software Alliance, the Motion Picture Association of America, the National Association of Real Estate Investment Trusts, the U.S. Grains Council and U.S. Meat Export Federation, among others.

The letter was addressed to the law committee of the Standing Committee of the National People’s Congress, China’s legislature, which issued the law in early May for public feedback. The letter was the culmination of weeks of discussions among a broad swath of associations and groups, people familiar with the matter have said.

Calls to the news office of the National People’s Congress rang unanswered late Thursday. The Chinese government has said nongovernmental groups would benefit from the law because it would clarify their legal status, though officials have said the law would also benefit national security. Thursday was the deadline for comments to be submitted in a Chinese feedback process.

In their letter, the groups said the scope of the law was overly broad, including in its definition of “nongovernmental groups” trade associations, overseas chambers of commerce, and professional associations, a move that the groups said could severely impact Chinese commerce and industry. They also raised concerns it would put management of such groups under the Ministry of Public Security, suggesting that Beijing sees the groups as a potential threat. Currently such groups work closely with a variety of commercial and other agencies.