<p>An extended two-phase hybrid-stress finite element method (X-THSFEM) is developed for fracture mechanics analysis of bimaterial interface cracks, to address the numerical difficulties caused by the oscillatory singular asymptotic crack-tip fields different from homogeneous cracked materials. Focusing on edge and central interface cracks with/without internal pressure, the asymptotic stress field function is introduced as an enhancement function into the two-phase stress fields to precisely characterize the near-tip stress oscillatory singularity. The complex stress intensity factors are solved by the least square method, and the effect of bimaterial property coupling on the factors is analyzed. Validations against theoretical solutions and benchmark results (ABAQUS, SBFEM) demonstrate high precision of the X-THSFEM: the maximum relative error of normalized K1​ is &lt; 0.6% and K2​ &lt; 6% for infinite bimaterial plates, and &lt; 9% for finite and multi-crack models. Endowed with higher-order stress fields, the X-THSFEM has high efficiency and precision, with a single element equivalent to thousands of conventional finite elements and the capability to model multiple interface cracks. It is applicable to both homogeneous and bimaterial crack systems, thus providing an effective numerical approach for dissimilar material interface crack fracture problems.</p>