Abstract: In this paper, along-fluctuating wind dynamic responses of tall buildingsystem under the control of Cross-Tensioned Spring Damper model mechanism(CTSD) are studied.Considering the tall building and its added CTSD as an integral coupling system as well as a nonorthogonally damped system, the paper develops a new stochasticresponse analysis method--Complex-Mode State Space Method based on thecombination of complex-valued modes, and derives the unified expressions for statisticalstate response and layer response solutions of the building. The calculation for a tall frame building and its results in contrast with those of non coupling real-mode responses are presented, which shows that the method proposed has its theoretical and applied values.