Paid search advertising has been a widely used marketing tool in both Chinese and English countries. Matching strategy greatly influences the effectiveness of paid search advertising. Extant studies have examined the matching strategy between keywords and ad content in paid search advertising using the English language. However, the rapidly growing Chinese paid search advertising market has been largely ignored. Different from the English market, the Chinese paid search advertising market has a comparatively greater use of synonyms. Considering the high semantic dependence of words and characters in Chinese, we develop a method to classify Chinese keywords according to the information complexity of the keywords. Based on the keyword classification, we use synonym-based matching, defined as the semantic similarity of ad content and the keyword, to study the bidding behavior of Chinese paid search advertisers. Our results indicate that synonym-based matching increases click-through rate, especially for complex keywords that have multiple search attributes. Both the empirical analysis using secondary data from the Chinese paid search market and a subsequent controlled experiment show the robustness of the results. Our results point to the need for understanding the local characteristics (especially language) when studying online paid search advertising in the Chinese market.