I used to give access to the cpanel to my staffs for uploading there works. So now after I am planning to take off this and give them only phpmyadmin access. So how can I make this possible ?
There is no way to do it through cpanel. The only way to do it would be to install phpmyadmin as a standalone - but it is somewhat involved. If your host allows remote connections, they could gain access to the database through a program such as mysql-front, just be aware that they would have the ability to completely destroy your entire database.