The invention provides a hollow pendulum barrel experiment device which processes data accurately and conveniently, is suitable for operation by students and is used for measuring gravity acceleration. The hollow pendulum barrel experiment device is composed of a hollow pendulum barrel and two sets of cylindrical weights with the same height and different radiuses. A compound pendulum system is formed by the hollow pendulum barrel and the cylindrical weights, first a swing period of the compound pendulum system is obtained after different amounts of weights are added, and a gravity acceleration computation formula is obtained by analyzing influences of the two sets of weights. Compared with an existing method, the gravity acceleration is obtained by fitting a slope of a straight line, thehollow pendulum barrel experiment device has the advantages of being simple in experimental method and convenient in data processing, the complex experimental data processing process is avoided, experimental data precision is improved, the experiment device is convenient to operate, a principle is easy to understand, and the experiment device is suitable for physics experiment teaching.