Such events as the constitutional revolution and the World War I in the early 20^th century imposed socio-political crises on the socio-political atmosphere of Qajar government. The most obvious consequence of the issues was more insecurity on the roads of Iran. The situation made it problematic for Iranian and foreigners who traveled through the roads and transported their goods. Moreover, the insecurity of Qaenat and Sistan, where colonial countries especially Britain had special attention to since the 19^th century, made it more significant. Britain tried to dominate the eastern Iran due to its significant goals and interests in India. This way, it would have defended its precious colony against Russia, though faced new challenges as the consequence of the insecurity and banditry on the roads of the two regions. Qaenat and Sistan were especially important to the foreign forces’ decisions in this period as the cities were located on the most significant commercial roads of the southeast Iran. Focusing on the library resources and taking a descriptive-analytical method, this study tried to explore the insecurities and banditries on the exchanging roads between the regions and Britain’s reactions to them. The results showed that banditry had been always a threat to the Iranian and foreign caravans, causing major damages to the local people and foreigners. On the contrary, British army defended their nationals against attackers and bandits to secure the regions, though they had encouraged sometimes bandits to achieve their own goals. The study concludes that Britain had conflicting behaviors regarding the security in Qaenat and Sistan regions. That is, sometimes they suppressed bandits and in occasions supported them to achieve their desirable goals.