A better comprehension of the impacts of online learning on student achievement is required considering the fast adoption of online education in China's higher education, especially in Nanchang city, driven by developments in technology and external factors such as the COVID-19 epidemic. The purpose of this research is to examine how certain aspects of online learning environments, students' technology use, and the efficacy of online instruction all influence students' final grades. The study used a quantitative research approach and surveyed 385 students from different colleges in Nanchang using structured questionnaires. The research used SPSS for statistical evaluation and adhered to a positivist ideology to guarantee objective and methodical data analysis. Recognizing the limitations in generalizability, simple random sampling strategy was utilized to target relevant individuals. According to the results, students' academic performance can be greatly affected by online learning platforms, provided that the necessary technology infrastructure and digital skills are in place. Key elements that contributed to the success of online learning included time management, improved interaction, and student involvement. Teaching methods and student engagement are significantly affected by instructors' and students' individual experiences with online learning, according to the study. Findings suggest that, with careful planning and consideration of both technology and pedagogical supports, online learning has the potential to replace conventional classroom instruction. The necessity to build online curricula that caters to students' varied requirements, train educators in online pedagogies, and invest in digital infrastructure are all policy and practical implications. By adding to what is already known about online education, this study paves the way for more adaptable, inclusive, and robust educational changes in the future.