This paper explores the grey model based PSO (particle swarm optimization) algorithm for fatigue strength prognosis of concrete. First, depending on concrete’s testing status, fatigue life is studied. Then, one GM(1,1) based PSO algorithm is used in fatigue strength prognosis of concrete. One important advantage of the proposed algorithm is that only fewer data is in need for fatigue strength prognosis. Finally, a case study is given to illustrate effectiveness and efficiency of the proposed approach.