In the present paper a micro-pelton turbine with very small dimension has been studied. This micro turbine was designed for 15 kW output power and was utilized in KhorasanRazavi. To analyze and evaluate the efficiency and effectiveness of physical and geometrical parameters, the turbine flow was simulated using the commercial software Ansys CFX 13 and the simulation results of the performance point were compared and evaluated with experimental results. Because of complexity of simulation and heavy computation, instead of entire turbine, just a part of it containing several buckets was simulated. A 3D transient flow simulation was applied using the SST turbulent model. In order to model two-phase flow, the standard homogeneous free surface model was employed. In the results the effect of rotating speed on the efficiency was investigated. Moreover, the effect of physical parameters: flow rate and head and geometric parameters: the distance from nozzle to the axis of buckets, the number of buckets in constant pitch circle diameter and constant bucket size, the number of buckets in constant pitch circle diameter and variable bucket size and the number of buckets in variable pitch circle diameter and constant bucket size on the performance of a micro-turbine was investigated.