NOVELTY - A built-in light source bioreactor or bioreactor with internal light source comprises: a reaction container (1), feeding and discharging device (3), light emitting device (2) and gas distributor (6). The reaction container is set with a cover plate (5) and the reaction container is for holding growth of micro-algae culture liquid. The light emitting device is set in the reaction container and when the reactor is operating, the light emitting device at least part or whole immersed in culture liquid, to provide micro-algae growth in container to provide desired light within container.    USE - As built-in light source bioreactor or bioreactor with internal light source for preparation of biomass diesel oil of microalgae (claimed).    ADVANTAGE - The built-in light source bioreactor is not limited by the weather change and provides the micro-algae breeding stage process; has strong controllability, which is good for a stable duration of industrial production; has reactors connected in series and/or in parallel so that a large scale cultivation of microalgae becomes more efficient.    DETAILED DESCRIPTION - A built-in light source bioreactor or bioreactor with internal light source comprises: a reaction container (1), feeding and discharging device (3), light emitting device (2) and gas distributor (6). The reaction container is set with a cover plate (5) and the reaction container is for holding growth of micro-algae culture liquid. The feeding and discharging device and the reaction container has sealed connection. The light emitting device is set in the reaction container and when the reactor is operating, the light emitting device at least part or whole immersed in culture liquid, so as to provide the micro-algae growth in the inner reaction container to provide the desired light within the container, where the light intensity of the light emitted by the light emitting device in the depth direction of the reaction vessel (Z-axis direction) is uniform or substantially uniform. The gas distributor provides gas to inner reaction container for the growth of microalgae in the container. An INDEPENDENT CLAIM is included for preparation of biomass diesel oil of microalgae, involving: (a) supplying the built-in light source bioreactor; (b) culturing biomass diesel oil of microalgae in the built-in light source reactor, where culturing involves first culture stage and second culture stage, where in the first stage of micro-algae growth, wave length of light by light emitting unit is 350-900 nm (preferably 570-800 and 400-500 nm), and in the second stage of micro-algae growth, wave length of light by light emitting unit is 350-900 nm (preferably 600-800 and 400 480 nm); and (c) recovering the algae from the built-in light source bioreactor.    DESCRIPTION OF DRAWING(S) - The figure shows a sectional perspective view of the built-in light source bioreactor.    Reaction container (1)    Light emitting device (2)    Feeding and discharging device (3)    Cover plate (5)    Gas distributor (6)