a sccessfful design of high pressure hydraulic valves requires thorough analysis of both velocity and pressure fileds with the aim of improving geometry to avoid cavitation . cavitation behaviour prediction of hydraulic valves and its associated perfomance drop is of high interest for the manufacturersand for the users .the paper present a  CFD  analysis of the flow inside a high pressure hydraulic valve .first the analysis was carried out without using cavitation models (single phase ) it was observed that absolute pressure was going below the vapour pressure .hence,it was required toturn on the cavitation model this model enabels formation of vapour from liquid when the drops below the vaporization  pressure .since the cavitation bubble grows in in liquid at low temprature ,the latent heat of evaporation can be neglected and the system can be consider  isothermal .under these conditions the pressure inside the bubble remains practically constant and the growth of the  bubble radius can be approximated by the simplified rayleigh equation .for typical poppet valve geometry ,of computational domain is assumed ,with pressure  inlet and oout let boundary condition ,and steady flow solution is computed because of the highly complex geometry of the hydraulic valve , the computational domain was meshed using unstructured grids using tetrahedral cells only.the paper presents numerical investigation of the flow inside a hydraulic valve using commercial CFD code CFD-ACE. the aim of the study is provide a good basis for futere designing of the hydraulic valve . the result indicated the cavitation zones which in turn suggest needs of modification of present geometry.