BEIJING — Prosecutors have charged one of China’s leading public-interest lawyers, Xu Zhiyong, with tax evasion, his lawyer said on Tuesday, continuing a government crackdown on this nation’s small band of activist lawyers and scholars that has lasted months.

Mr. Xu, 36, is a founder of the Open Constitution Initiative, known in Chinese as Gongmeng, a nonprofit group that often has taken on high-profile cases involving citizens’ civil rights. The government shut down the organization’s Gongmeng legal center on July 17, three days after accusing it of tax violations, and the police seized Mr. Xu on July 29.

In an interview on Tuesday, his lawyer, Zhou Ze, said Mr. Xu was formally charged on Aug. 12. Mr. Xu could face seven years in prison if he is tried and convicted. The prosecutors now must seek an indictment, but that is widely considered a formality.

The government’s main accusation is that Mr. Xu’s group failed to pay taxes on a $100,000 grant from Yale University that was earmarked for the legal center. But human rights advocates and foreign political analysts agree that the charges are politically inspired, part of what seems to be a growing effort by security officials to shut down independent activism and especially activism that is supported with foreign funds.

The government has moved this year to block many foreign-based Web sites and social-networking services used by Chinese activists and, often, by Chinese citizens. It also has taken action against a host of activist scholars and lawyers, effectively disbarring about 50 lawyers earlier this summer. Gao Zhisheng, whose aggressive legal campaigns earned him a reputation as a gadfly, has not been heard from since being taken into custody more than six months ago.

A number of activist lawyers have been beaten or harassed by unidentified assailants while working this year on cases. And one of China’s most prominent political dissidents, Liu Xiaobo, has been held virtually incommunicado in a suburban Beijing detention center since December.

Separately, the Beijing financial publication Economic Observer reported on Tuesday that the government had begun a broad inquiry into the so-called resident representative offices of foreign-based enterprises — in essence, offices that many foreign groups, including many charities and nonprofit organizations, establish on Chinese soil.

The newspaper quoted an unnamed source as saying that the government was drafting new regulations governing the offices and that many of the existing offices were suspected of violating Chinese law.

The current rules exempt the offices from paying taxes but also bar them from conducting business activities. The unnamed source was quoted as saying that many offices have flouted that prohibition, while others are guilty of lesser violations like failing to report address changes or renew expired registrations.

The report stated that investigators had already begun visiting some resident representative offices. In at least some instances, the investigators have been accompanied by the police, Nicholas Bequelin, a researcher with the Hong Kong office of Human Rights Watch, said in an interview on Tuesday.

The government’s move against Gongmeng and Mr. Xu, he said, has sent a chill sweeping over China’s activist organizations, in large part because Gongmeng is widely seen as one of the most scrupulous groups working to expand the rule of law. Indeed, Mr. Xu, a professor at Beijing’s University of Posts and Telecommunications, has been an elected member of a local governing body, the People’s Congress in Beijing’s Haidian district, since 2003.

“He was doing everything aboveboard,” said Mr. Bequelin, who called Mr. Xu “the voice of moderation” in public-interest legal circles. “If he goes down, who is safe?”