In Iran, annually, one million people in the country have been migrating in recent years. The paper aims to study of internal migration (between counties) in Iran using spatial approach and explain it in the context of development. We used secondary analysis of 2011 census for 397 counties. Global and local indicators of spatial association, and TOPSIS, GEODA, ARC GIS were used for data analysis. The results showed Iranian counties have different levels of development, as well as, development of counties has spatial structure and cluster distribution. According to the Global Moran's I statistic, crude migration intensity inwards (CMIIj), strongly, and crude migration intensity outwards (CMIOj), poorly, tend to concentrate clusters in space. Local Moran's test results showed that the development, positively with immigration rate and negatively with emigration rate is correlated. Although, the same pattern of relationship is not followed by all counties. The results distinguished four patterns of relationships; high-high (high development-high migration), low-low (low development-low migration), high-low (high development-low migration), and low-high (low development-high migration). And also, the relationship of development and migration is not significant for some of counties. In conclusion, if centralization and unequal development continued, movement and migration flows will continue and even increase in the future.