After news of the 228 Incident spread to Tamsui, some young people in the area discovered that there were rifles, used for military education during the Japanese colonial period, hidden at Tamkang High School. They seized these rifles and attempted to attack Nationalist soldiers, which became one of the reasons that government took away Principal Tân Lêng-thong later on.

During the 228 Incident, Tamkang High School student Koeh Hiáu-cheng was murdered by soldiers on the street. The school principal, Tân Lêng-thong, and the director of the educational affairs, N̂g A-thóng, helped arrange his funeral affairs. The next day after they returned home, Tân Lêng-thong, Tân Ōng (Tân Lêng-thong's father), and N̂g A-thóng were taken away by the soldiers. Lô͘ Oân, another Tamkang High School teacher, went out upon hearing that the principal had been seized, but he was shot and later died from his injuries.

The school was named Tamsui Middle School until April 1947, after which it was renamed Tamkang High School due to restructuring.