The invention relates to a three dimensional stability assessment method for an open pit slope based on unmanned aerial vehicle remote sensing. The method comprises three processes, namely unmanned aerial vehicle slope field monitoring, slope rock and soil material parameter testing, and computer analysis and assessment. The three dimensional stability assessment method for the open pit slope based on the unmanned aerial vehicle remote sensing provided by the invention uses an unmanned aerial vehicle to realize all-weather 360-degree dead-corner free scanning and monitoring on three-dimensional shapes of the slope, and can timely and accurately acquire influences of blasting vibration, atmospheric rainfall, vehicle rolling and so on during the period of mining the open pit on the three-dimensional shapes of the slope, so as to carry out stability assessment, and the result is more in line with the actual condition of the slope shape; besides, stability assessment can be given to the slope dynamic evolution state in real time according to the demand of the mine, and the timeliness of an analysis result is strong; distribution characteristics and safety factors of a displacement field, a stress field, and a plastic zone of the slope can be given in real time, and an optimized analysis of the slope angle and height can be performed; and monitoring and assessment can be carried out on other landslide, railway, road slope and other complex terrain regions, and the adaptability is stronger.