Performance assessment requires the demands of accountability, implementation of the control functions and development needs of local government organizations in the handling and prevention of floods in the region. The method used in this research is qualitative method. Data collection techniques are carried out using participatory observations, interviews and documentation studies. Data analysis is done with descriptive techniques through three flow of activities that are one unity, namely: data reduction, data presentation and conclusion drawing. The results showed the performance assessment of the Gunung Mas District Disaster Management Agency on the prevention and preparedness of flood disasters from the aspect of understanding the auth and aspects of work accuracy tends to be many activities in the field of disaster prevention and preparedness carried out and aspects of innovation, work speed and cooperation are still minimal socialization of disaster-aware culture through simulation in the field and the lack of innovation in the field of disaster prevention and preparedness.