[Aim] Eriosoma lanigerum, an important quarantine pest in the world, could cause serious harm to the apple tree. In recent years, E. lanigerum spread far in China and caused serious damage. Studying the molecular ecological changes during its invasion can provide basis for comprehensive control.[Method] We made six microsatellite markers to explore the genetic diversity dynamics of E. lanigerum from six areas (Yantai, Weihai, Qingdao, Weifang, Liaocheng, Taian) in Shandong Province from 2012 to 2015.[Result] The genetic diversity of E. lanigerum gradually reduced over time in all six areas. The genetic diversity in 2012 was significantly higher than in later years, and no significant differences were found from 2013 to 2015. Genetic diversity expressed as the value of gene alleles observed (Na) and expected heterozygosity (He) had a tendency to gradually reduce over time. E. lanigerum in all six areas went through the bottleneck effect, detected by analysis of IAM (infinite allele model), TPM (two-phased model of mutation) and SMM (stepwise mutation model), which mainly caused reduction of genetic diversity. The number of alleles and the genetic diversity index in microsatellite loci Erio20, Erio75 and Erio78 decreased over time.[Conclusion] The locus of Erio20, Erio75 and Erio78 are the main loci to cause the decrease of genetic diversity of E. lanigerum. E. lanigerum may have evolved a "super clone" genotype to adapt to different environments in China and increase the diffusion range.