Abstract:[Purposes] In order to study the disjoint path cover (DPC for short) problem, the structures of 1-disjoint path coverable, 2-disjoint path coverable and k-disjoint path coverable that still maintain the DPC property after deleting vertices and passing through specified edges are discussed on the unit interval graph. [Methods] Using the structural characteristics of unit interval graphs and the structural properties of path cover, the paired many to many k-DPC fault tolerance problem of unit interval graphs is studied by mathematical induction and counter proof method. [Findings] Arbitrarily delete p vertices and pass through q edges, the unit interval graph G is still paired k-DPC, if and only if G is (2k+r-1) -connected, where (p+q)≤r. [Conclusions] The fault tolerance path cover problem of unit interval graphs is closely related to Hamiltonian properties and connectivity. The research results and methods provide a theoretical basis for the research of paired k-DPC fault tolerance of interval graphs, and help to design an effective algorithm to find paired k-DPC fault tolerance on unit interval graphs.