Antibiotic resistance has become one of the major public health threats of the 21st century. Bacteria serve as an excellent model organism, allowing scientists to study evolution in a short amount of time. There are many misconceptions among students regarding the emergence of bacterial resistance. Conducting experiments on the selective effects of antibiotics on bacteria in high school biology teaching can provide students with a more intuitive understanding of natural selection. This study designs a set of simulation activities: representing antibiotic resistance genes with letters and simulating the degree of antibiotic resistance with numbers. It simulates bacterial reproduction under no antibiotic pressure, in an antibiotic environment, and in a high-dose antibiotic environment. The simulation activity describes the significance of antibiotic resistance to health care while allowing students to better understand the directional role of natural selection in biological evolution and to dispel common misconceptions surrounding the mechanisms of antibiotic resistance.