The invention discloses an electric automobile short-term backup capacity assessment method comprising the steps that the parameters in the electric automobile charge/discharge contract considering the user traveling demand are determined; the charge/discharge feasible region influencing the electric automobile charge/discharge path is given; the power boundary constraint and the electric quantityboundary constraint influencing the electric automobile backup capacity are given based on the charge/discharge feasible region; the minimum electric quantity constraint line is calculated; the discharge depth of the electric automobile and the discharge frequency constraint within a single scheduling cycle are given by considering the battery life constraint; and the calculation method of the electric automobile backup capacity is given based on all the constraints. The short-term backup capacity of the electric automobile can be rapidly assessed.