Search for Squark and Gluino Production in Multi-jets plus Missing $E_t$ Final States at Tevatron

We present preliminary results on the search for squarks and gluinos in proton-antiproton collisions at $\sqrt{s} = 1.96$~TeV at Tevatron, based on about 400 pb$^{-1}$ of data collected by the CDF experiment in Run II. Events with multiple jets of hadrons and large missing transverse energy in the final state are studied within the framework of minimal supergravity and assuming R-parity conservation. The measurements are compared to Standard Model predictions and new extended limits on the gluino and squark masses are extracted.