Forest fragmentation of the Lam basin was studied with the aid of the Infragmentation tool in GIS, with satellite imagery and current basin land use maps. The results show that the forest landscape of the Lam basin is fragmented into four main types: core forest, patch forest, edge forest and perforated forest, of which the core forest occupies the largest area and is divided into three categories: small core forest, medium core forest and large core forest. The forest landscape in the upper of Lam River varies from 2007 to 2017 with the following major trends: large core forest area increased 2.5%, the rest reduced.