The research focuses its objectives on the concept of scientific addition in theses of Usul al-Fiqh that were registered in Saudi universities, for the master’s and doctoral levels, especially since this term raises deep questions and contemporary research method books have not been able to define what it is and highlight its foundations at the level of specialization, and it is no secret that a condition such as scientific addition is conditional for obtaining academic degrees - master's and doctorate, its limit and concept must be regulated and not let loose depending on relative estimates. Therefore, the research sought in one of its aspects to highlight these scientific additions through master's and doctoral theses in order to determine their foundations.