22 years old. According to Zhihu's query, 18 years old graduated from high school, and studied for 4 years as an undergraduate. 18 plus 4 equals 22 years old, so the undergraduate graduated at the age of 22. Undergraduate students are students who receive undergraduate education. Unlike junior college students, undergraduates can get a bachelor's degree after graduation. In China's general college entrance examination, undergraduate admission is divided into early batch, one batch of undergraduates (one), two batches of undergraduates (two) and three batches of undergraduates (three batches of undergraduates were cancelled in some areas on 20 17).