Abstract: This paper explores the relationship between asset impairment and comparability of accounting income, and finds that the more accounting income is affected by asset impairment, the less comparable it is. When the proportion of allowance change in total assets increases by 1%, the comparability of accounting income would decrease by 3%-5%. Additional analysis shows that both conservatism principle and earnings manipulation behavior related with asset impairment can lead to the lack of comparability among firms. These results indicate that (1) to achieve global comparability of accounting information, IASB should be cautious about developing asset impairment standards; (2) firms may implement the same asset impairment standards using different criteria according to their own reporting incentives. Consequently, comparability of accounting information cannot be completely achieved through accounting standards convergence. Thus, this paper provides reference on how China should continue the international convergence of accounting standards (especially IFRS9).