It is provided in the Constitution that regional autonomy shall be practiced in areas where people of minority nationalities live in concentrated communities and the power of autonomy shall be exercised. The national autonomous areas shall include the autonomous regions，autonomous prefectures and autonomous counties，among which the autonomous counties account for the highest proportion. Legislation power is the core of autonomy power for national autonomous areas. By analyzing the basic theories of legislation power in the autonomy power of autonomous counties，this article carries out research on the autonomous legislation of four national autonomous counties in Chongqing from such aspects as the practices of autonomous legislation，exercise of flexible legislation power and dilemma in autonomous legislation and puts forward relatively specific legislation optimization suggestions therefor.