As an important teaching method in the era of education informatization 2.0, the smart classroom has become a hot topic in terms of whether it can really improve students’ learning effectiveness. Many scholars have carried out empirical studies in this field, but the conclusions are not the same. By the use of meta-analysis, this study quantitatively analyzes 48 experimental and quasi-experimental studies in China and other countries to explore the smart classroom’s effect and influencing factors. The results show that, on the whole, the smart classroom has a better-than-average promotion effect on students’ learning effectiveness; from the perspective of moderating variables, the learning outcome of smart classrooms is influenced by the factors of learning stage, knowledge type, teaching cycle, class scale, and equipment condition, but is not moderated by the factors of subject, teaching strategy, and evaluation tool. Specifically, smart classrooms can become a suitable partner for large-class teaching, short-term courses, and experimental courses. However, the misuse of technology and equipment should be avoided in the application process.