Abstract: A new pumpless internal circulation photobioreactor for hydrogen production, including: an outer reaction barrel and an inner reaction barrel made of transparent materials, a gas collecting device, and an air duct arranged between the inner reaction barrel and the outer reaction barrel. An outer ring-shaped reaction chamber is formed between the inner reaction barrel and the outer reaction barrel. Liquid permeation holes and air holes are arranged on the inner reaction barrel. The gas collecting device is communicated with the outer ring-shaped reaction chamber. The air duct is communicated with the interior of the inner reaction barrel and the outer ring-shaped reaction chamber. The present invention has a simple and compact structure and is easy to operate, and gas produced by the reactor can be re-introduced into the reaction solution to provide aerodynamic power for stirring the reaction solution, which realizes low energy consumption and high-efficiency hydrogen production.