Abstract: Differences in characteristics of population agglomeration areas significantly affect migration. Research on the effect of location-specific characteristics of population agglomeration areas on migration would enrich the study of population geography and provide references for territorial function zoning and the provision of public service facilities. This article explores the effect of pull factors of population agglomeration areas on migration by investigating immigration in Dongguan, Guangdong Province in the period between 1995 and 2000, when the number of immigrants increased most rapidly. Based on the classic push and pull theory, an indicator system was built to calculate the pulling effect of population agglomeration areas. The relationship between different pull factors and population aggregation was analyzed using principle component analysis and multiple regression analysis. The results show that population aggregation varied greatly between different towns and its distribution was spatially uneven in Dongguan. There was a very large number of immigrants aggregated during 1995-2000 and the population aggregation was affected by employment opportunities, per capita income, and the migration path dependence in different towns. The large number of labor-intensive manufacturing industries characterized the industrial development in Dongguan, which provided great employment opportunities for migrant workers from areas lacking job opportunities. The large number of specialized industrial towns gained economies of agglomeration, which led to rapid economy growth and high salary that attracted lots of immigrants to the city. Migration path dependence also affected the immigration. The migrants often followed their predecessors' destination choices. This imitative behavior comes from the consideration of reducing migration risk and cost. These migrants are often countrymen or relatives. The early immigrants often help the late comers for example by introducing the latter to the companies they work and sometime providing accommodations for the new comers. Areas absorbed immigration in earlier period would attract more immigrants in the next period because of the migration path dependence. The regressive equation of the comprehensive pulling force and population aggregation was a cubic curve. The relative importance of the three pull factors to population aggregation, from most significant to least significant, is migration path dependence, employment opportunities, and per capita income. As a typical population aggregation area, Dongguan attracted a large number of immigrants. At the same time, some push factors such as the household registration system, high level of consumption and high housing price also expel the immigrants. This paper does not discuss the push factors because these factors are difficult to quantify, and the expelling force was less than the pulling force in areas of population aggregation. In addition, this paper only focuses on the immigration in Dongguan between 1995 and 2000. Surplus labor during this time period in China was abundant. Therefore, migration path dependence was significant. These three factors may affect migration differently in a different time period and a new relationship would require more empirical studies to test.

Key words: Dongguan City, employment opportunities, migration path dependence, per capita income level, population aggregation, spatial variation