A number of eye-catching cases are still lingering. China National Offshore Oil Corporation was kept out of the bidding for Union Oil Company of California due to national security concerns.

China's IT heavyweight Huawei is banned from making any investment in the United States, as the country sees telecommunications as one of its most sensitive sectors for foreign investment.

"Those cases had sent the wrong signals to the Chinese companies and made them scared," Lewis said. "In fact, as long as you keep a distance from certain sensitive sectors, the United States is quite open to foreign investment," he added.

"In general, the United States is open to foreign investment, but the national security is their bottom line," Tian Deyou said.

When Chinese President Xi Jinping visited the United States this September, the two countries agreed to limit the scope of their respective national security reviews of foreign investments solely to issues that constitute national security concerns, and not to generalize the scope of such reviews to include other broader public interest or economic issues.

"We hope the US government honors its commitments and gives Chinese companies fair treatment," Tian said.

"The US government tends to give equal treatment to foreign investors. But the state-owned companies from China usually receive additional scrutiny. Fair or not, that's the real practice," Lewis said.