At least 130 protesters were arrested and some of the demonstrators and policemen were injured in the scuffle.
The protesters reached the metal gate of the fortified compound and were kicking and trying to push it open when police armed with bamboo batons rushed to the scene and began beating them.
"Stop the killing, stop the killing," the protesters chanted as they charged toward the office gate.
Tibetans have protested in front of the Chinese Embassy visa office in the heart of Katmandu in the past, but it was the first time they had reached the gate and tried to push through.
Sunday's protest was the latest by Tibetan monks and refugees in Katmandu against Chinese authorities' crackdown on recent demonstrations in Tibet.
Police officials, who spoke on condition of anonymity citing policy, said those arrested were being held in several detention centers and would likely be freed later within hours without facing any charges.
Nepal has said it would not allow protests against any "friendly nation," including China.
International rights groups, like New York-based Human Rights Watch, and the United Nations have repeatedly criticized Nepal's handling of the Tibetan protests and beating of the protesters.
Nepal has not issued any statement on China's crackdown in Tibet.
China Accuses Dalai Lama Of Closing Door To Talks Following New Tibet Protests
Chinese state media accused the Dalai Lama on Sunday of closing the door to talks over Tibet's future, an apparent response to rising international calls for Beijing to negotiate with Tibet's exiled Buddhist leader.
In a lengthy article, Xinhua News Agency cited past actions and statements attributed to the 72-year-old Nobel Peace Prize winner that it said contradicted or undermined his calls for negotiations.
"It was the Dalai Lama clique that closed the door of dialogue," Xinhua said, using China's standard term for the Tibetan government-in-exile.
The statement came a day before the arrival in Beijing of the Olympic torch, which has become a magnet for Tibetan activists and other groups seeking to use the August Games to draw attention to their cause.
China has accused the Dalai Lama of orchestrating protests in Tibet's regional capital Lhasa and other heavily Tibetan areas that started peacefully among Buddhist monks, but turned deadly on March 14. Beijing says 22 people were killed in Lhasa, while Tibetan exiles put the overall death toll at 140.
China's Premier Wen Jiabao told Hong Kong media in Laos Sunday that Lhasa is "basically stable," and that "social order has returned to normal."
Wen reiterated China's position that it is open to talks with the Dalai Lama if he gives up his desire for independence, and acknowledges that Tibet and Taiwan are inseparable from China.
Officials with Lhasa's municipal government described the city as calm Sunday, a day after a protest reportedly broke out at a monastery there. The officials said they were sending text messages to area residents telling them not to "believe or pass on rumors of unrest."
A woman who answered the phone at Lhasa government headquarters said the reported protest on Saturday was merely a rumor.
"You shouldn't believe such things," said the woman, who hung up without giving her name. No new incidents were reported on Sunday.