The purchase agreement in China is governed by China Civil Code and the intellectual property right assignment agreement is the part of the purchase agreement. However, the intellectual property rights and goods, which of them are all subjects of sale, are very different. Accordingly, whether the intellectual property right assignment agreement can also be governed completely by China Civil Code would be an issue. In addition, should the provisions of Taiwan Civil Code, which is not the same but similar with China Civil Code, completely be applied to the intellectual property right assignment agreement? If so, do these need to be adjusted or reinterpreted for such kind of agreement? It could be another issue. Based on this, this article is to analyze and discuss the responsibilities of warranty for free of defect regard to the intellectual property right assignment agreement under Section – Sale of China Civil Code.