This article focuses on the inhibitory effect exerted by house price bullish sentiment on adverse selection in resale housing markets. Firstly, theoretical methods are developed for the bullish sentiment index (BSI) and the adverse selection level (ASL). Economics experiments were then designed to study the resale housing market characteristics in different bullish sentiment environments. The BSI and ASL were calculated from the experimental data to study the effect of bullish sentiment on the adverse selection. The research shows that severe information asymmetry is the main cause of adverse selection in the resale housing market. The bullish sentiment of traders in the market temporarily restrains the adverse selection to some extent. The degree of information asymmetry should be reduced to minimize the adverse selection problem in the resale housing market.