The group reports that Beijing forced 1,000 refugees from the Kachin ethnic community to Myanmar, formerly known as Burma, where the refugees are said to be at risk of abuses.
Bill Frelick, refugee director for Human Rights Watch, said China is called on to provide the refugees with temporary shelter in nearby Yunnan province.
"China is flouting its international legal obligations by forcibly returning Kachin refugees to an active conflict zone rife with Burmese army abuses," he said in a statement from New York.
In a report published in June, Human Rights Watch said as many as 10,000 Kachin refugees have fled conflict and abuses in Myanmar since June 2011.
Kachin rebels and other ethnic groups are battling for more self-rule. Myanmar's President Thein Sein has tried to broker peace agreements with ethnic rebels but talks with the Kachin group have failed.
Clashes in Kachin state, in northern Myanmar, broke out in April, leaving at least 31 people dead. Ethnic conflict in the region broke out last year for the first time since a peace deal was brokered in 1994.