Abstract: Adam Smith and Immanuel Kant are two influential moral philosophers in the European Enlightenment Age. Adam Smith took up moral sentimentalism in the Scottish Enlightenment, focused on the mental analysis of moral sentiments. He suggested that in according to the mental function of sympathy of human being’s sociality, make the moral judgement based on the “inter-subjective” mirror of society, and try to find out the root and mental ground of “sentimentalism”. The moral metaphysics of Immanuel Kant’s transcendental idealism suggested that the “inner” transcendental reason is the root of morality, and the transcendental pure practical reason grounded the “moral law”. Adam Smith’s moral philosophy centered on the propriety, and Immanuel Kant’s moral philosophy emphasized duty. These two kinds of moral philosophies, represented the difference between the low standard of morality in British empiricism and the high standard of morality in German Rationalism.