1．Chengdu University of Technology College of Physics，Chengdu 610000，China;2．Chengdu University of Technology School ofMathematical sciences，Chengdu 610000，China
Abstract: Spectrometer experiments play an important role in university physics experiments，and thederivation of the minimum deflection angle calculation formula is complex，so it is rarely mentioned in mostphysics experiment textbooks．Based on this，this paper proposes to use two simple methods，function derivationand trigonometric function，to derive and explain the principle of the formula of minimum deflection angle．Inaddition，in view of the shortcomings of the experimental process of finding the minimum deflection angle inconventional physics experiments，such as large blindness and long experimental time，this paper proposes amethod to quickly locate the minimum deflection angle of the triangular prism，the repetition method，which caneffectively improve the accuracy and success rate of the experiment while reducing the experimental difficultyand human uncertainty，simplifying the operation procedure and shortening the experimental time by
coordinating the green cross light source and the objective lens．
