I assume that you are asking about the series of revolts in the Arab world that are often referred to as the "Arab Spring." These revolts have been caused largely by the fact that the people of most Arab countries have been denied the opportunity to rule themselves in any meaningful way. They have also been caused by the corruption of the governments in these countries.
All of the revolts in the Arab world have been against autocratic governments. This is true of the protests against Ben Ali in Tunisia, Mubarak in Egypt, Assad in Syria, and others. These rulers have consistently prevented meaningful free elections from happening. They have suppressed political parties and freedom of speech because they have said the suppression is necessary for security. In addition, they have presided over corrupt regimes that have enriched themselves and their families, friends, and allies. As regular people in the Arab world have seen these things happening, they have become more and more frustrated. When Mohammed Bouazizi killed himself in Tunisia, a spark was lit that has ignited these frustrations and caused the revolts that are still going on.