Actually the whole process like this:
1. I need export the solution(name is, for example, my_abc) from dev instance and be going to import into sandbox instance to same name solution.
2. Before import it into sandbox instance, I have backup the Product entity by create a solution named my_backup and only left one entity Product.
3. After import my_abc into sandbox, the soluton in sandbox(name also my_abc) has been totally replace by the solution from Dev instance.
4. now in sandbox, I want to use the Product entity in my_backup solution to replace the Product entity in my_abc solution.
How to do that?
Sorry for so much confusion, anyway I want to keep the customization of Product entity in sandbox NOT be overwrote by the same entity from dev instance.
Thanks.