Aiming at the problem of degradation of system frequency modulation performance caused by uncertain transmission delays, system parameters and load disturbance, communication bandwidth constraint and calculation burden, and the intermittent generation of wind power, in this paper, a Sampling PI Load Frequency Control（SPI-LFC） scheme is proposed considering the signal sampling period and transmission delay. And the exponential decay rate is introduced to evaluate the rapidity of the system. Firstly, a sampled-data-based delay-dependent SPI-LFC model of a time-delay power system with wind power is constructed. Then, by constructing a new two-sided closed-loop Lyapunov functional and applying linear matrix inequalities technology, the sampling period of system, the stability margin of communication delays, and the stability criterion and SPI control design method related to exponential convergence rate are derived. The simulation results show that the proposed scheme has a larger sampling period, communication delay stability margin, and large exponential decay rate. And it also has strong robustness against uncertain system parameters, load disturbance, and the intermittent generation of wind power.