Economic sector is one of sector which supporting activities' people exchanging living needs. Being divided economic sector become formal economic sectors and informal economic sectors. District Tembalang is one sub-district in the city of Semarang, Central Java Province, since 1996 become expansion area Diponegoro University (UNDIP). Initially this region is form gardens and agricultural areas, when the Diponegoro University start building its first campus in Tembalang, this area was growing rapidly and at present becomes solid so necessary support facilities to support the activities of the academic community UNDIP as a resident. One of supporting economic sector is informal economic sector, which also increases exponentially year, therefore it is necessary to study. The method in this research begins with a field survey using hand phone and software help MAPPT to get data coodinates and interview to get the attributes of each sector of the informal economy in 2011 and 2016. The results of data collection was processed and analyzed using ArcGIS and nearest neighbourhood methode so known distribution pattern and economic sector conditions every category. The results of the analysis is divided into three main sections, they are at the pattern of spread of the informal economy as a whole, the pattern of spread of the informal economy every category, and the distribution pattern of economic sectors based on the distance to the centroid of Diponegoro University campus. All results of the analysis showed that clumped distribution pattern, and have a direction of growth to the southeast, with a standard deviation ellipse centroid shift is 67,36015 m.