A crossbow comprising: a body and an activator pivotably mounted on the body, the body having a shooting device, a first safety device and a string connected thereto, the shooting device having a trigger, the string located at a front end of the body, the activator located at a rear end of the body and having an extension which extends toward the body, the extension pulling the string and hooking the string to the shooting device, the first safety device pressing one end of the trigger to restrict the trigger from being pulled, characterized in that; a second safety device is located between the body and the activator, the second safety device presses the first safety device and restricts the first safety device and the trigger from being activated when the activator is pivoted, the second safety device has a rod and a contact member, the rod is pivotably connected to a first end of the contact member, a second end of the contact member is pressed by the activator, when the activator is pivoted, the activator is removed from the rod, and the rod pivots the contact member, the contact member contacts the first safety device to restrict the trigger from being pulled, when the activator is pivoted back and positioned at the body, the rod is pushed by the activator and pivots the contact member, the first safety device is not restricted, and wherein, when the activator is pivoted, the activator is removed from the rod, the rod pivots the contact member and the contact member contacts the first safety device to restrict the trigger from being pulled, the extension pulls the string and hooks the string at the shooting device, the activator is pivoted back and positioned at the body, so that the rod is pushed by the activator and pivots the contact member so that the first safety device is not restricted, an arrow is installed to the body, when the first safety device is applied by a force, the trigger is not restricted by the first safety device, when the trigger is pulled, the shooting device releases the string which shoots the arrow away. a body and an activator pivotably mounted on the body, the body having a shooting device, a first safety device and a string connected thereto, the shooting device having a trigger, the string located at a front end of the body, the activator located at a rear end of the body and having an extension which extends toward the body, the extension pulling the string and hooking the string to the shooting device, the first safety device pressing one end of the trigger to restrict the trigger from being pulled, characterized in that; a second safety device is located between the body and the activator, the second safety device presses the first safety device and restricts the first safety device and the trigger from being activated when the activator is pivoted, the second safety device has a rod and a contact member, the rod is pivotably connected to a first end of the contact member, a second end of the contact member is pressed by the activator, when the activator is pivoted, the activator is removed from the rod, and the rod pivots the contact member, the contact member contacts the first safety device to restrict the trigger from being pulled, when the activator is pivoted back and positioned at the body, the rod is pushed by the activator and pivots the contact member, the first safety device is not restricted, and wherein, when the activator is pivoted, the activator is removed from the rod, the rod pivots the contact member and the contact member contacts the first safety device to restrict the trigger from being pulled, the extension pulls the string and hooks the string at the shooting device, the activator is pivoted back and positioned at the body, so that the rod is pushed by the activator and pivots the contact member so that the first safety device is not restricted, an arrow is installed to the body, when the first safety device is applied by a force, the trigger is not restricted by the first safety device, when the trigger is pulled, the shooting device releases the string which shoots the arrow away.