I am working in Dubai. Before I worked in Dubai transport company as a taxi driver, I work there one year. After I live this company I am working other company still I have Dubai transport visa this (Haraam) or not?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

The Muslims must abide by the laws that regulate work which are set by the president for the interest of the country and its people and long as these laws are within this intention. The president has the right to restrict what is permissible if he sees that there is a considerable religious benefit in doing so. If working for another company with a work visa obtained by a previous company which sponsored you, causes harm to you or to that [first] company, then it is not permissible for you to continue that kind of work without a permission from the authorities in order to protect the lives and wealth of people. 

Allaah knows best.