This paper tries to make a philosophical speculation towards the"uncertainty"of"true-being"from the following three aspects:first, Chuang Tzu's philosophy on skepticism and the uniformity of all things reflected on"Chuang Zhou's Dreaming of Becoming A Butterfly";second, Descartes'skepticism on the existence of true being;last, the ongoing exploring of the true being. Through the reflections on different philosophers'speculations towards the same proposition, the belt between Chinese and western philosophy is built, providing a broaden horizon and thinking mode towards life.