This paper constructs a new measure of investor attention using the self-selection information from Xueqiu website，that is，AXQA( abnormal Xueqiu attention) ，which can capture the level of investor attention more directly and accurately． Through examining the relationship between AXQA and market performance， this paper finds that investor attention will result in short-term pressure on market price and trading volume． Besides，this paper constructs proxies for synchronous-attention，for pre-attention and for post-attention，and finds that synchronous-attention plays a more important role in determining market performance than pre-attention． However，market data influence post-attention more than synchronous-attention． Attention during nontrading period will be reflected in the opening price of the following trading day． Finally，this paper proposes a trading strategy based on AXQA，which performs much better than the CSI 300 index．