Abstract: Location and determine the size distributed generation units that changing the reactive current radial network significant impact on reducing losses, improving voltage profile and voltage stability. Improper placement can in some circumstances these advantages reduce or even and even risk the entire system operators. In this thesis, Optimal location using voltage stability index, and size of distributed generation units using water cycle algorithm is obtained in radial distribution network. After determining the candidate bus for the integration of DG, the search method optimum size and location DG to minimize total power losses and improve voltage profile, determines using the water cycle algorithm. As well as active and reactive power the network is calculated, and the results were compared. Results IEEE 33-bus using MATLAB, Tested and the results are analyzed.