An object tracking method includes following steps: transmitting search information for searching for an object by a first processor during a search stage; receiving the search information and using a second processor to determine whether any of at least one accessory camera has captured an object image in the search stage. When the second processor determines that at least one of the at least one accessory camera has captured the object image, the second processor transmits notification information to the first processor and the first processor enters a tracking stage and transmits request information to the second processor. When the second processor receives the request information, the second processor performs one of the following: transmitting the object image to the first processor, wherein the first processor calculates an object pose according to the object image.