The invention relates to an automatic clamping system. The automatic clamping system comprises a main frame, a driving assembly used for driving the main frame to move is arranged on the main frame, a first arm and a second arm are arranged on the main frame, a first lifting assembly is arranged between the first arm and the main frame, a second lifting assembly is arranged between the second arm and the main frame, a clamping assembly is arranged on the first arm, a spraying assembly is arranged on the second arm, the spraying assembly comprises a plurality of spraying units, and each spraying unit corresponds to one and merely one die-casting die local area. The automatic clamping system and a detection method thereof have the effects that a controller obtains the temperature, detected by each spraying unit, of the corresponding die-casting mold local area and compares the temperature with the preset temperature of the current material, so that spraying of cooling liquid to the die-casting mold local area corresponding to the current spraying unit or stopping of spraying of the cooling liquid is controlled, the temperature of each die-casting die local area will not be too high or too low, and the problem in the related technology that temperature difference exsists among local portions since integral spraying is performed on the die-casting die is solved.