The objective of this study is to analyze the characteristics of texts with different topic intimacies and verify the effects of topic intimacy on writing based on this analysis. To this end, this study had 50 second-year high school students mark their intimacy to 30 topics. Then, the characteristics of texts were analyzed after the students submitted three pieces of writing with different topic intimacies. The results are as follows: First, content and structure showed a significant difference depending on topic intimacy, but expression did not. Second, as a result of analysis by grouping the students based on their writing level, the high level showed no score differences in content, structure, and expression depending on topic intimacy, while the middle and low levels showed a significant difference in content and structure. Third, characteristics of texts related to content and structure were extracted, and there was a difference in all four characteristics (diverse and rich contents, closeness of argument and basis, refutation against expected counterargument, and cohesion of sentences or paragraphs) according to topic intimacy.