The gravity gradiometer has important application value in resource exploration, geophysical research, autonomous navigation and other fields. The gravity gradiometer based on atom interferometers is a new type of high-precision measuring instrument, and its miniaturization and practicality are the core problems to be solved in its wide application. We design and implement a compact high-precision atom gravity gradiometer capable of measuring horizontal components. The instrument adopts the technical scheme of combining all-quartz vacuum cavity and accessory frame, which reduces the volume of the sensor part to 105 L. It adopts a double-sided optical modular structure, which reduces the volume of the optical unit to 36 L. These evolutions make the instrument very easy to carry. In laboratory, the sensitivity of the instrument is measured to be 320 E/$\sqrt[]{\mathrm{H}\mathrm{z}}$, and the resolution is 3.3 E@4800 s (1 E=1×10^-9 s^-2).