In the present paper, a numerical study is performed for analysis of 3D effects of geometrical parameters namely microchannel depth, eccentricity and sizes of rotors and operational parameter namely pressure difference on flow flux and efficiency by LBM. In investigation of simultaneously variation effect of geometrical parameters namely rotors eccentricity and microchannel depth is observed in all depths, increasing the eccentricity, both flow flux and efficiency increased. Also, in a constant eccentricity both flow flux and efficiency increased. In the next investigation that simultaneously effect of geometrical parameters namely rotors sizes and microchannel depth is discussed determined that in all depths, decreasing the rotors sizes, flow flux decreased. But for efficiency, it became less in the lower depths and increasing depth the efficiency increased. In final, the effects of operational parameter of pressure difference and geometrical parameter of microchannel depth on flow flux and efficiency has been studied. As the results show, increasing the pressure difference, flow flux linearly decreased so that it became zero at the certain pressure. Moreover, efficiency variations vs. pressure difference parabolically is observed.