The invention discloses a diatom growth variable research system based on a square diatom culture frame. The diatom growth variable research system is characterized by comprising a culture chamber, wherein the culture chamber is provided with an air conditioner and the square diatom culture frame in a rectangular framework structure, the top of the square diatom culture frame is provided with a filament lamp light source and an electrification duration control switch, the four corner parts of the square diatom culture frame in the horizontal direction are provided with four guide posts, support plates in horizontal arrangement are arranged among the guide posts, container positioning grooves are arranged on the support plates, the four corner parts of the support plates are provided with guide sleeves capable of being glidingly sheathed on the guide posts, positioning screw bolts used for positioning the support plates after the sliding of the support plates are also screwed and connected onto the guide sleeves, and the diatom growth variable research system also comprises a color control mechanism horizontally arranged between the light source and the support plates. The system provided by the invention can realize the regulation and control on various variables including the diatom growth so that the influence condition of each variable on the diatom growth can be conveniently researched, and meanwhile, the diatom growth variable research system has the advantages that the structure is simple, and the variable regulation and control is very convenient and fast.