The report by the National Computer Network Emergency Response Coordination Center of China, China's primary computer security monitoring network, said 47,000 overseas Internet Protocol addresses were involved in the attacks, Xinhua reported.
Most of the overseas IP addresses originated in Japan, the United States and South Korea, the center said.
"China has become the world's biggest victim of cyberattacks," said Zhou Yonglin, an information security official from the Internet Society of China.
The report also said 1,116 domestic Web sites had been breached by overseas hackers.
"Generally speaking, malicious IPs based in the U.S., Japan and [South Korea] posed the greatest security threat to China last year," said Wang Minghua, vice director of the center's operations department.
The center will work more closely with other countries to improve computer security, Zhou said.