Tuberculosis (TB) is one of deadly infectious diseases. The ordinary treatment for this disease is by using antibiotics, within non stop duration of 6 months. There are many cases for many reasons, that patients receive treatment less than required duration of treatment. This condition, called improper treatment, unfortunately could lead to Multi-drug Resistant Tuberculosis (MDR-TB) which is resistant to the first line antibiotics and need a longer duration of treatment. In addition, in simplified case, the improper treatment of MDR-TB also could lead to similar case; called Extensively-drug Resistant Tuberculosis (XDR-TB). The cases of MDR and XDR-TB recently already increasing in many parts of the world. In this paper, a mathematical model that can be used to explain phenomena of MDR-TB and XDR-TB, and its simulation is presented.