Abstract: A certain part of helicopter is a part of pivotal, and it is easy to produce fatigue crack in local area, according to the design requirement the part shall be under fluorescence penetrant inspection after service. However, due to the influence of the surface, the fatigue crack can′t be detected effectively by penetrant inspection. Based on the characteristics of the part, through analyzing the principle, condition, effect, and enforceable of penetrant and eddy current inspection, an inspection proposal of experimental investigation was developed. The results show that the fatigue crack can be detected effectively by using the method of penetrant and eddy current inspection together.