This article observes the general nature of environmental change in the Pleistocene of East Asia, including that of the Korean Peninsula, by contextualizing it with the simple and indistinct variation of East Asian palaeolithic assemblages. The evidence of hominin occupation increased markedly from the latter half of the Mid-Pleistocene in East Asia. The climate then had been mild and pleasant with the influence of Asian monsoons; accordingly, Asian hominins used to depend on plant resources rather than animals under less stressful environmental conditions. This ecological trait and the low hominin population level were possibly responsible for the less-accentuated characteristics and unwitnessed temporal variation of East Asian lithic assemblages. As of MIS 4 in the Late Pleistocene, however, the environmental condition severely deteriorated and hominins turned to more frequent animal exploitation. The changing environmental context led hominins to take more vivid technological advancement and inspired them to yield unprecedented temporal and spatial lithic variation across the Asian continent; the number of palaeolithic localities in the Korean Peninsula rapidly increased during the short, warm MIS 3. The production of handaxes in the mid-Korea seems to have emerged as a result of regional traditions formulated under this hominin-environment interaction of the period.