In order to consider the uncertain influences of wind power on the power system reserves， this paper introduces a probability density function of the wind power forecast error and a mathematical model of spinning reserve based on the chance-constrained programming. The uncertain and stochastic factors， like the load and wind forecast errors， the fault outage of generators are considered. by setting a constraint condition that the probability of the spinning reserve satisfied is larger than the given confidence level， the model reflects the influence of abundance level of spinning reserve on the economy of system. The analysis shows that under the premise of system reliability， the economy of this model is better than that of traditional models， and the reliability is higher when the wind power forecast error obeys the probability distribution. At the same time， the model can realize the balance between the reliability and economy of system by selecting reasonable confidence levels.