The disclosed embodiments relate to a photovoltaic mobile lab configured for performing on-site test in a photovoltaic module. The photovoltaic mobile lab includes a transport vehicle, a first container, a second container, and a light source. The first container is fixed on the transport vehicle. The second container is slidably sleeved on the first container. The second container and the first container together form a testing chamber. The light source is configured for providing illumination to the photovoltaic module. The light source and the photovoltaic module are respectively accommodated in the first container and the second container and are respectively located at two opposite ends of the testing chamber so that a distance between the light source and the photovoltaic module is changeable while the second container is sliding with respect to the first container.