Abstract: In recent years, the active enhancement of heat transfer with electric field has drawn a wide attention in the field of heat transfer. Since the complex mathematical model as well as the strong nonlinear couplings between multi-physics, the theoretical analysis and experimental studies on this field are relatively few. In this paper, the lattice Boltzmann method is adopted to studied the two-dimensional electro-thermal convection in a partially heated cavity. The effects of dimensionless parameters such as Rayleigh number Ra, electric Rayleigh number T, length of electrode plate h, and the distance from the center of electrode plate to the lower wall \delta, on the heat transfer efficiency are investigated, and the bifurcation structure of the electro-thermal convection is also analyzed. Numerical results show that as the number of electric Rayleigh number T increases, the heat transfer efficiency gradually increases, and the bifurcation type for electric Rayleigh number T is usually subcritical. while the bifurcation type for the Rayleigh number Ra is supercritical. In addition, when the electric Rayleigh number T is larger enough, the coulomb force is dominant over the buoyancy force, and the effect of the Rayleigh number Ra on heat transfer coefficient is insignificant. Further, a comparison of the heat transfer efficiency of the various electrode positions shows that the heat transfer efficiency is optimal when the electrode plate is in the middle of the left sidewall, and the smaller the length of the electrode plate, the more efficient of the heat transfer. The results of this article extend the existing two-dimensional electro-thermal convection model, and it can provide a reference for theoretical analysis of other electro-thermal convection problems with non-uniform temperature boundary.