Biological invasion is becoming more important disturbance factor to the structure and function of ecosystem as well as to the bio-industry such as apiculture. Since the invasion of the black thorax yellow-legged hornet, Vespa velutina nigrithorax Buysson, 1905 into Busan port, the southeastern part of Korea in early 2000s, gradual spread of the hornet was observed. The rate of spread was estimated as 12.4 km/yr, which was 5.6 times slower than that from France, 67.3 km/yr. The diffusion coefficient (D) is still in increasing phase, implying the greater risk of spread. Community structure of Vespa was different before and after the invasion. After V. velutina invasion, the survey on 2010 from Gyeongnam province showed 67% of V. velutina and reduced proportion of the smaller size hornets such as V. analis, V. crabro and V. simillima simillima compared to the bigger sized hornets such as V. mandarinia or V. ducalis. Research on the suppression of population size and spread as well as the method to protect the ecosystem health and apicultural industry is urgently requested.