Lesson Study (LS) has been considered to be a novel approach to preparing and teaching lessons in the education system of Vietnam and applied to all schools nationwide. However, it has not been included in the educational teacher training curricula at the undergraduate level. Consequently, pre-service teachers may not only get a keen sense of what LS is but also face lots of trouble preparing an appropriate lesson plan (LP) which reflects the LS approach. Hence, this study aims at enhancing the pre-service biology teachers’ (PBTs) understanding of the LS and developing the biology lesson plan (LP) by using the LS process. The research paradigm used in this phase is a mainly qualitative case study and a descriptive statistics design. Six female PBTs in their third year were chosen randomly from the volunteers to participate in the research. Before participating in the LS training workshop, the percentage of six PBT’s understanding of the LS was at 0.0%. However, after participating in the LS training workshops (LSTW), the six PBTs had a better insight into the LS and how to use the LS process to construct better biology LPs, which was proven by the average of 85.7%. After participating in the LSTW, the entire PBTs recognized that LPs were team products and building better biology LPs was not so easy as it seemed. The LP was constructed based on the team collaboration in which all members shared their experiences.