In this study, an algorithm for determination of hydrological and oceanic effects on gravity variations is introduced. Also, these effects on gravity variations for the case of Maule earthquake is  being surveyed. For this purpose, data set of GLDAS hydrological model, JASON1 altimetry and World Ocean Atlas (WOA) is applied. With the help of hydrological model, the hydrological effects in land are computed and with combination of data of altimetry satellite and WOA, the oceanic effects in the ocean are calculated. This data is in the form of equivalent water layer thickness which is converted to mass changes. Then, this data is transformed to spherical harmonic coefficients using spherical harmonic analysis which is being used to compare gravimetric satellite observations such as GRACE. The hydrological and oceanic effects on gravity variations for the case of Maule, have maximum and minimum value about 2 and -0.5 microGal in radial direction, about 2 and -2 microGal in northward direction and about 0.6 and -0.6 microGal in eastward direction. Moreover, variations of these effects due to gravity variations in this region are 4 microGal which is a remarkable value for the aforementioned earthquake and is necessary for detecting tectonic signal.