The invention belongs to the technical field of inorganic nanomaterials, and particularly relates to a method for controllably synthesizing niobium pentoxide microspheres and microflowers without template solvent heat. The method comprises the following steps: firstly, mixing a certain amount of niobium inorganic matter ionic salt with a precipitant according to a certain ratio, and respectively dissolving into two different organic solvents; then performing ultrasonic treatment for 15-30 minutes, completely dissolving solid powder and evenly mixing; and finally, respectively transferring thetwo solutions into a reaction kettle with a polytetrafluoroethylene substrate, sealing, putting into a drying oven, controlling the temperature of the drying oven to be 180-200 DEG C, reacting for 8-12 hours, and after the reaction is over, cooling the product to be at room temperature; centrifugally separating the precipitated product, collecting solids, rinsing for multiple times with deionizedwater and absolute ethyl alcohol, and performing vacuum drying, to obtain the niobium pentoxide microspheres and microflowers.