The COVID-19 epidemic in 2020 posed a sudden and serious challenge to education where online teachings were adopted, and problems that people had not noticed before were exposed. Based on the experience of international online course and the study of online teaching, the paper focuses on the associated problems and puts forward some solutions. First, based on the performance of current software and hardware used in online teaching, the characteristics of commonly used teaching software have been analysed and compared. Then, efficient combinations of teaching software for complementary advantages are recommended to ensure a high-quality online teaching. Second, problems inside of class existing in online lecturing and learning are studied, and corresponding teaching methods have been explored including the aspects of class interaction design and implementation, alternative method for delivering essential video information, and online class management. Finally, some objective class evaluation criteria are studied in terms of coverage of class content, learning effect of specialized knowledge, and online class interaction. In the end, some feasible solutions are provided, and it can be served as a reference to improve the online teaching.