This paper proposes and analyzes a pavement fatigue life prediction method for asphalt and cement concrete pavements. A theoretical frequency domain analysis involving pavement fatigue life was conducted. By using the vehicle-road coupled vibration system model, the random vibration between a vehicle and road caused by road roughness was analyzed. In this paper, it is proposed that the random power spectral density of the vehicle-road coupled vibration is a useful tool to predict the fatigue life of pavements, and the corresponding prediction procedures are proposed, aimed at providing some reference for long-life pavement design and performance evaluation.