Pandemic covid 19 make teaching system has been changed. Online teaching system is one of the solutions can be made by the government to handle education system in a country such as Indonesia. Online teaching system which has various shapes such as blog, classroom learning which is facilitated the World Wide Web; a mix of online instruction and meeting the class known as additional models or hybrid; or the full online experience, where all the assessment and instruction is done electronically. Object relationship of learning and constructivist educational philosophy and concerned that online learning has the orientation which is basically a constructivist ideology, where the combination of some of the knowledge is an inquiry-oriented activity and authentic and also promote the progress of the construction of new knowledge. Description of the online teaching system in theory and practice can be illustrated in a few examples that have been found in the research that has been done and found new discoveries obtained in the study, but not everything can be done because of several factors. Please note that the components in the online learning system can serve as a learning system which is very strong influence on learning in the class. The objective of this research is critical of online teaching system in theory and practice that can be applied by teachers in the teaching process in the classroom. The results obtained in this study were teachers and students need extra effort to make online classes. Further research is needed on appropriate strategies in order to determine the next result is more useful. There some advices for any studies that discuss online teaching system are done in certain areas, namely the use of electricity and other disciplines such as social and humanities.

Key Words: pandemic covid 19, education system, Online teaching, e-learning, web, and virtual class.