E-learning is a form of teaching with several advantages, especially in the context of disease outbreaks such as COVID-19. In terms of teaching at High Schools, E-learning lectures are utilized both for direct classroom teaching and for online teaching via the Internet. This article presents a dual-use electronic lecture design model (DUEL) with iSpring Suite, which can be flexibly used for both classroom and online learning goals. An empirical research on DUEL is conducted in Mathematics at high school. After the experiment, a survey that evaluating the effectiveness of using DUEL has sent to learners. The feedback results showed that the first step of using DUEL was received quite positively and had developed to their full potential in fluctuations of today’s teaching context.