The invention relates to a micron-grade monodisperse silica microsphere preparation device with a transparent glass reaction kettle and a blender, the transparent glass reaction kettle is provided with an ultrasonic generator; the transparent glass reaction kettle is externally provided with a horizontal pushing pump, a material outlet of the horizontal pushing pump is located on the upper part of a stirring head of a stirrer, the micron-grade monodisperse silica microsphere preparation device is also provided with an electronic microscope, an electron microscope lens is located on the transparent glass reaction kettle wall, and the micron-grade monodisperse silica microsphere preparation device is also provided with a constant temperature device. By the design of feed rate, rotational speed and the ultrasonic frequency, the uniform and spherical degree of synthesized micron-grade monodisperse silica microspheres can be effectively improved, the size control of the micron-grade monodisperse silica microspheres can be effectively improved, in addition, through observation of numerical value of the electron microscope, particle size and monodispersity of the monodisperse silica microspheres can be directly identified.