To improve conventional sensitivity factor analysis for load flow calculation that only considers three bus types: PQ, PV and Vθ, this paper proposes a sensitivity factor analysis method for bus type extended load flow calculation. By considering PQV, Qθ, QV, PQVθ extended bus types, this paper derives the sensitivity factor calculation formulas based on the correct equations of bus type extended load flow. Numerical tests given in this paper show that, when new bus types are involved in a load flow calculation, the precision of conventional sensitivity analysis method reduces obviously, whereas the proposed method can still obtain a better result. It also demonstrates the effectiveness of the derived sensitivity analysis method. By applying the proposed method, it can increase the accuracy in large-scale networks and better simulate the change of load flow.