It is better to choose a degree than a non-degree in the topic selection of correspondence undergraduate thesis. Basic principle of topic selection: professional principle: the topic selection must be related to the major studied. Scientific principle: we should pay attention to the theoretical value and practical value of the research topic and avoid the common sense problems that have been completely solved. Feasibility principle: the topic selection should be combined with the researcher's own ability and research conditions to avoid choosing a big topic that is difficult to be competent.