Abstract：The right to alter is not a right of the author to alter his/her own work, but a right to prevent others from altering the work ．The nature of the right to alter provided by Regulation on Protection of Computer Software is different from the same right provided by Copyright Law. The latter is a moral right, while the former is an economic right. Computer program protected by copyrights means sequence of code-based instructions, so it is not a copy-right infringement to only alter data used by instructions, instead of altering instructions. Users are allowed to alter computer software to improve its function and performance in the process of operation of the software by using any tools. Manufacturers and distributors of tools to alter computer software shall not bear direct or indirect liability, if they do not distribute altered version of software or induce or intentionally facilitate direct infringement.