The invention relates to the technical field of photochemical equipment and discloses an adjustable photochemical reaction box. The adjustable photochemical reaction box comprises a box body, a sample frame and a control system, wherein the box body comprises a bottom plate, a cover plate, a left side plate, a right side plate, a front side plate and a back side plate; light sources are arranged on the inner surfaces of the left side plate and the right side plate; fans are arranged on the front side plate and the right side plate; the sample frame is fixed on the bottom plate and is parallel to the left side plate; the sample frame is provided with a temperature sensor; the control system comprises a temperature control module, a light control module and a timing module; the input end and the output end of the temperature control module are connected with the temperature sensor and the fans respectively; the light control module and the timing module are connected with the light sources respectively. The adjustable photochemical reaction box can be used for controlling the illumination intensity, the reaction temperature and the illumination time in the reaction box and the accuracy of an experiment is improved.