将脉动风速及其非线性项引入到桥梁的自激力公式中 ,运用随机微积分理论与矩方程理论 ,得到双方向运动的桥梁断面的一阶矩与二阶矩的微分方程组。通过微分方程的数值方法 ,得到扭转驱动的桥梁断面随机振动的时程曲线 ,从而得到随机失稳的临界风速。研究表明 ,脉动风速非线性项使得扭转驱动的桥梁趋于稳定 The pulsating wind speed and its nonlinearity are introduced into the bridge self-excitation formula. By using the theory of stochastic calculus and moment equation, differential equations of the first moment and the second moment of a bridge cross-section are obtained. By numerical method of differential equation, the time history curve of torsional-driven bridge section random vibration is obtained, and the critical wind speed of random instability is obtained. The research shows that the nonlinear term of fluctuating wind speed makes the torsionally driven bridge tend to be stable