||The Kosa School in China is a school of the Hinayana Buddhism, the thought of which is based on Vasubandhu’s Abhidharma-kosa. This school has great influence on various schools of Chinese Buddhism. And the practitioners of Kosa are called ‘Teachers of Kosa’. The main doctrine of teachers of Kosa is that all physical and mental phenomena are made up of conditions, thus there is no permanent and independent existence. This theory goes against the theories of substance and self of the Tīrthika Schools. The Kosa School classifies matter, mind and other forms of existences into 5 sets and 75 elements. They further assert that although these elements are indivisible, they are subject to conditions for arising and fading out. Current existence arises and the past existence fades out, and this is the process of all phenomena. Things arising must have conditions causing it to arise, therefore they have the doctrines of the ‘six causes’, ‘four conditions’, and ‘five effects’ etc, implying that all phenomena arise according to causes and conditions and cannot exist independently. There is neither permanent and independent existence nor any substance or self of things. This school builds its theory on the notion of ‘elements exist while the self of every phenomenon does not exist’ and establishes two categories of causes and effects, namely, the ‘youlou’ (maculate) and the ‘wulou’ (immaculate). This thesis tries to collect the research works of modern scholars on the topic of the Kosa, expose the theoretical framework of the Kosa, and explain its theories of time, no-self and Vasubandhu’s view on karma. Key words: Kosa School, Vashuvandu, Hinayana , Abhidharma-kosa, Kosa sect.