Tacit knowledge is an essential foundation for developing students’ learning ability, especially in understanding and solving problems. However, the transforming of tacit knowledge confront a big challenge during the outbreak of Corona Virus Disease 2019 (COVID-19), because most teaching and learning activities were conducted in online context, which impair a face-to-face interaction. To explore the effect of tacit knowledge on students’ learning ability in the online learning environments, the current study based on SECI model (The Socialization, Externalization, Combination, and Internalization) proposed to design the tacit knowledge transformation teaching approach. To assess the effectiveness of this approach, 60 elementary school students were recruited in the quasi-experiment. The results of retention test and transfer test showed that the experimental group, using the tacit knowledge transformation teaching approach, has significant improvement on learning ability than the control group. The current research theoretically provide a teaching strategy on tactic knowledge, and practically helps teachers to organize instructional activities, thereby, advocating the appropriate use of social media.