Nature of the Indochina blocks is not only important to Tethys study but also important to the Cenozoic deformation style of the Tibetan Plateau. There is little knowledge from the North Laos which locates inner of the Indochina. Our study shows most of the granites in North Laos are related to the closure of the Tethys, a few related to Caledonian orogeny. TDMC ages of zircon Lu-Hf in North Laos cluster around 1.8~1.6 Ga, other ages cluster around 1.4~1.2 Ga. The zircon U-Pb and TDMC age peaks in North Laos are similar to the ages got in other areas of Indochina block, indicating the same basement in the Indochina block. The age peaks are also similar to that of the Changdu-Simao peaks, indicating the possibility of the same basement of the Indochina-Simao untied block if the Dien Bien Phu belt between the blocks is not ophiolite suites. The united block should be the same basement with the Yangtze block in Rodinia era due to the same age peaks around 4.0~3.5 Ga, 2.0~1.8 Ga, and 1.4~1.2 Ga.