This paper presents a 3-D analytical modeling of Gate engineered tri-gate Silicon-On-Nothing (SON) MOSFET. Solving the 3-D Poisson's equation, surface potential distribution of the device is obtained. In addition, results for threshold voltage and electric field of the device are also shown. Moreover response of the proposed device towards the various Short channel effects like Hot carrier effect, threshold voltage roll-off has been examined. Analytical results are validated using the simulation results as obtained from ATLAS, a 3-D device simulator from SILVACO.