［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.