An automatic transfer switch, comprising: a stationary contact, comprising a stationary arc contact point and a stationary main contact point, and configured to receive current from a power supply, a movable contact, comprising a movable arc contact point and a movable main contact point, being pivotally connected to a load and capable of pivoting between a closing position contacting with the stationary contact and a opening position not contacting with the stationary contact, an electric arc extinguishing chamber, comprising a plurality of grid pieces, and configured to eliminate an electric arc generated when the movable contact and the stationary contact are switched off, wherein, the stationary contact comprises a first part and a second part which are connected at an angle, the first part is configured to receive current from a power supply, the second part is configured to be in contact with the movable contact, and an end of the second part extends to be flush with an upper edge of the grid pieces of the electric arc extinguishing chamber, and a flow direction of current in the second part of the stationary contact is approximately opposite to a flow direction of current in the movable contact, so as to provide a Lorentz force to an electric arc generated during disconnecting towards the electric arc extinguishing chamber, wherein the movable contact comprises two movable main contact points, characterized in that the movable arc contact point of the movable contact is closer to an end of the movable contact than the movable main contact point, so that the movable arc contact point contacts the stationary contact before the movable main contact point when closing, and the movable arc contact point of the movable contact contacts the stationary arc contact point of the stationary contact and the movable main contact point of the movable contact contacts the stationary main contact point of the stationary contact after connecting, the movable arc contact point comprises a first movable arc contact part and a second movable arc contact part, the first movable arc contact part comprises a first branch and a second branch, and the second movable arc contact part comprises a third branch and a fourth branch, the first branch and the second branch form an L-shape, and the third branch and the fourth branch form an L-shape, and the first branch is arranged on a side surface of a movable contact body and contacts the movable contact body, the second branch is fixed to a main surface of the movable contact body, the third branch is fixed to a main surface of the movable contact body, the fourth branch is arranged on another side of the movable contact body opposite to a side surface contacting with the first branch, and a gap is formed between the second branch and the third branch. a stationary contact, comprising a stationary arc contact point and a stationary main contact point, and configured to receive current from a power supply, a movable contact, comprising a movable arc contact point and a movable main contact point, being pivotally connected to a load and capable of pivoting between a closing position contacting with the stationary contact and a opening position not contacting with the stationary contact, an electric arc extinguishing chamber, comprising a plurality of grid pieces, and configured to eliminate an electric arc generated when the movable contact and the stationary contact are switched off, wherein, the stationary contact comprises a first part and a second part which are connected at an angle, the first part is configured to receive current from a power supply, the second part is configured to be in contact with the movable contact, and an end of the second part extends to be flush with an upper edge of the grid pieces of the electric arc extinguishing chamber, and a flow direction of current in the second part of the stationary contact is approximately opposite to a flow direction of current in the movable contact, so as to provide a Lorentz force to an electric arc generated during disconnecting towards the electric arc extinguishing chamber, wherein the movable contact comprises two movable main contact points, characterized in that the movable arc contact point of the movable contact is closer to an end of the movable contact than the movable main contact point, so that the movable arc contact point contacts the stationary contact before the movable main contact point when closing, and the movable arc contact point of the movable contact contacts the stationary arc contact point of the stationary contact and the movable main contact point of the movable contact contacts the stationary main contact point of the stationary contact after connecting, the movable arc contact point comprises a first movable arc contact part and a second movable arc contact part, the first movable arc contact part comprises a first branch and a second branch, and the second movable arc contact part comprises a third branch and a fourth branch, the first branch and the second branch form an L-shape, and the third branch and the fourth branch form an L-shape, and the first branch is arranged on a side surface of a movable contact body and contacts the movable contact body, the second branch is fixed to a main surface of the movable contact body, the third branch is fixed to a main surface of the movable contact body, the fourth branch is arranged on another side of the movable contact body opposite to a side surface contacting with the first branch, and a gap is formed between the second branch and the third branch.