Dmitry Medvedev said in a telegram to Hu Jintao: "If necessary, we are ready to provide help in tackling the consequences of this disaster." He also conveyed condolences to the families of those killed.
It was earlier reported that over 900 students were buried by collapsed buildings as the earthquake, measuring 7.8 on the Richter scale, shook China's southwest province of Sichuan.
China's official news agency Xinhua agency said that it is still difficult to estimate the scale of the destruction, as telephone links with the province have been cut off, but that about 80% of the buildings and other facilities near the epicenter of the quake have been destroyed.
Premier Wen Jiabao has traveled to the site to oversee the relief operation. The military is also reported to have been sent to the area.
The U.S. Geological Survey said the quake struck at 2:28 p.m. local time (06:28 GMT), and that its epicenter was 57 miles (92 km) northwest of Sichuan's provincial capital, Chengdu.
Tremors were also felt some 930 miles (1,500 km) away in the capital, Beijing, where office workers rushed out into the streets as their buildings shook.