The wide application of ecommerce has brought about new ethical challenges while changing traditional business models, and it is urgent to construct corresponding ethical norms. The close technical and ethical connections between big data technology and ecommerce make it possible to build the latter with the former. The application of data mining in electronic commerce is the whole process. Through the use of big data technology, the basic norms of ecommerce ethics are introduced into the whole process of the operation of ecommerce platform in a preset manner, so as to establish an ecommerce ethics norm commensurate with operability and normalization.