Liang, who was appointed to the post in March, said the contact signalled an important step in long-term and strategic Sino-U.S. interests, Xinhua news agency reported, citing a statement from the Defense Ministry.
During the call, Liang called on the United States to end arms sales and military ties with Taiwan and Gates told him that they would stick to the "one-China" policy, Xinhua said.
The "hot line" is similar to one created decades ago between Washington and Moscow. The Pentagon initially proposed the Beijing hot line, but the Chinese balked until President George W. Bush and President Hu Jintao agreed last September to establish the system.
Pentagon spokesman Bryan Whitman said Gates and Gen. Liang Guanglie spoke briefly about advancing military-to-military relations, and Gates noted the importance of having a direct telephone link.
"It demonstrates that overall the U.S.-China defense relationship continues to improve," Whitman said.
Gates congratulated Liang on his March 17 appointment as minister of defense, and he "emphasized how substantive dialogue can avoid any miscalculations."
Liang, a career officer and full general, formerly headed the Nanjing Military District that would be responsible for operations against Taiwan, the self-governing island that Beijing claims as its territory.
Taiwan split from the mainland in 1949, and China has threatened to invade if it formally declares independence. Taiwan-U.S. military ties and weapons sales have been a source of discontent for China.
