A charging apparatus with dynamical charging power is configured to charge an electric vehicle. The charging apparatus includes a main power conversion unit, an auxiliary power conversion unit, and a control unit. The main power conversion unit receives an AC power and converts the AC power into a main output power. The auxiliary power conversion unit receives an auxiliary DC power and converts the auxiliary DC power into an auxiliary output power. The control unit controls maximum output power of the main output power to be an upper-limit output power value. When a charging power value of charging the electric vehicle is greater than the upper-limit output power value, the control unit dynamically controls the auxiliary output power according to a power difference value between the charging power value and the upper-limit output power value.