The present study is purposed to apply to the Korean economy the generality of the theory which contends that export concentration is in some degree correlated with instability of export earnings, according to Massell, Coppock, Hirschman and etc. in order to measure Korea`s export trend and instability in comparison with measured results of international study. Since most of the studies conducted for analysis of this correlationship on emphirical basis have shown an almost uniform patterns, its applicability deserves to be tested in the framework of the Korean economy. Though measurement process for the Korea`s export concentration and instability indices involves a number of somewhat irrational prepositions, the obtained results can be construded as follow : First, in parallel with high Korea`s export concentration indices, her export is also shown highly instable. Second, Korea`s export earnings have been rapidly increased as her export commodity concentration index gradually reduced annually. Third, contrary to the feature obtained from international study, Korea`s export earnings have grown as export geographical concentration disperses wider annually. Fourth, one of the most instable factors in Korea`s export earnings is clarified to be products of the primary industry, export of which is highly influenced by versatile annual harvests or productions. And fifth, it may be concluded that, in term of a short-term projection, the prospect of Korean export is rather optimistic in consideration of those concentration indices which have been decreased gradully year by year.