Diagnosability plays an important role in measuring the reliability of multiprocessor systems.In this paper,it is proved that in the PMC model,the (*n*+1)-dimensional Folded Hypercube is (*n*+2)-diagnosable with the precise diagnosis strategy for *n*≥3,and (2*n*+2)/(2*n*+2)-diagnosable with the pessimistic strategy for *n*≥4.