This paper proposes a method of three-phase voltage phase and frequency locked loop in order to reduce the influence of traditional PLL under distorted voltage conditions like voltage dip, frequency mutation, phase mutation, harmonics injected. This paper tells how αβ-PLL works under the conditions of ideal power grid. On this basis, this paper introduces the positive and negative first-order complex filter which has a quality of selectivity, by improving the filter structure and designing its parameters reasonably, positive-sequence fundamental voltage is detected accurately under αβ coordinate system. The simulation result shows that this method can make the amplitude, frequency and phase of positive- sequence fundamental voltage be locked faster and more accurately.