By　embedding　cohesive　interface　elements　into　solid　finite　element　meshes,　two-dimensional　crack　propagation　of　Koyna　gravity　dam　under　earthquakes　was　simulated.　The　simulated　cracking　process　and　final　crack　pattern　were　compared　favorably　with　experimental　results　and　numerical　ones　available　in　literatures,　they　agreed　well.　It　was　shown　that　the　proposed　method　is　effective　to　simulate　crack　propagation　and　expanding.