Abstract: A target acquisition device and a system thereof called ArmConnect™ are disclosed. The target acquisition device of the present invention comprises an optical module, an image sensor, a compass, an acceleration sensor, an accessory connector, a display and a sight control circuit. The target acquisition system of the present invention comprises a target acquisition device, a range finder and a mobile device, wherein the target acquisition device further comprises a wireless transmission module for connecting to the mobile device. The range finder is connected to the target acquisition device by the accessory connector. Some assistant devices, such as a remote control, a weather station, a night vision, a recorder, a camera and etc., can also be connected to the target acquisition device for providing supports to make the ammunition hit the target.