Until now, the academic situation indicates that Lao Tzu hold negative attitude towards "knowledge". It's probably because of the thought of the "desirelessness". People aspire after knowledge of science and technology owing to cupidity. Therefore, we think Lao Tzu negate the pursuit of knowledge. However, the meaning of "Yu" in Lao Tzu can not only refer to cupidity but refer to an innate trait. This thesis calls it "Yu Xiang". People aspire after knowledge not only because of cupidity but also because of "Yu Xiang", and it's recognized and is valued by Lao Tzu. In the pursuit of "Learning" and "Dao" are compatible, and both of them are important cultivation that we have to equally emphasize on.