With the effect of load transfer on the feasibility of maintenance scheduling taken into full account， an optimization model is developed for security check of maintenance scheduling that considers the constraint of load transfer. The model takes the minimum of weighed quadratic sum of load transfer and load shedding as the objective function， and determines constraint equations such as the nodal power balance equation considering load transfer and load shedding and the upper and lower limits of transmission power， load transfer， load shedding and so on， which is based on the AC power flow model. The model can evaluate not only the feasibility of maintenance scheduling， but also the plan of load transfer or adjustment when the maintenance scheduling is infeasible. Hence the proposed model is of great significance for security check of maintenance scheduling. This paper solves the above-mentioned optimization problem with the semi-smooth Newton method， whose effectiveness is verified by tests on an IEEE 14-bus system.