This paper presents a systematic analysis of wash trading activities in four popular NFT markets. The study analyzes over 25 million transactions to explore the evolution of wash trade activities. A heuristic algorithm is proposed that integrates transaction network characteristics with behavioral analysis to detect wash trading. The findings indicate that NFT markets with incentive structures have higher proportions of wash trading volume. Specifically, the LooksRare market has a wash trading volume proportion of 94.5%, while X2Y2 has 84.2%. The paper also introduces a graph-based algorithm to detect wash trading by analyzing strongly connected components and binary/ternary relationships in the transaction network. The results show that wash trading is more prevalent in markets with reward mechanisms, such as LooksRare and X2Y2. The study highlights the impact of reward mechanisms on wash trading activities and suggests that reducing incentives can decrease wash trade occurrences. However, addressing the issue requires intricate market regulatory mechanisms and enhanced transparency. The paper also emphasizes the need for further research into incentive structures and market behaviors to develop more nuanced regulatory frameworks. The study concludes that wash trading significantly affects market dynamics, leading to artificially inflated trade volumes and potential long-term sustainability challenges for NFT markets.This paper presents a systematic analysis of wash trading activities in four popular NFT markets. The study analyzes over 25 million transactions to explore the evolution of wash trade activities. A heuristic algorithm is proposed that integrates transaction network characteristics with behavioral analysis to detect wash trading. The findings indicate that NFT markets with incentive structures have higher proportions of wash trading volume. Specifically, the LooksRare market has a wash trading volume proportion of 94.5%, while X2Y2 has 84.2%. The paper also introduces a graph-based algorithm to detect wash trading by analyzing strongly connected components and binary/ternary relationships in the transaction network. The results show that wash trading is more prevalent in markets with reward mechanisms, such as LooksRare and X2Y2. The study highlights the impact of reward mechanisms on wash trading activities and suggests that reducing incentives can decrease wash trade occurrences. However, addressing the issue requires intricate market regulatory mechanisms and enhanced transparency. The paper also emphasizes the need for further research into incentive structures and market behaviors to develop more nuanced regulatory frameworks. The study concludes that wash trading significantly affects market dynamics, leading to artificially inflated trade volumes and potential long-term sustainability challenges for NFT markets.