On the basis of the results of Lin et al. [12], the interaction between screw dislocations and an internal crack in a two‐phase medium is analyzed. The complex potential, stress field, stress intensity factor, crack extension force and strain energy are derived. The mechanical behavior of the medium is strongly influenced by the shear modulus ratio of the two‐phase medium and the dislocations inside the internal crack. Finally, our results can be reduced to several special cases.