The speed regulating stirrer used in the laboratory is driven by a single-phase capacitive asynchronous motor with compact structure, which is suitable for mixing low to medium and high viscosity liquid in the laboratory. It can be used with various mixing rods, such as anchor type, propeller type, four blade type, stainless steel mixing rod type, etc. to meet various experimental needs. It is a commonly used biochemical analysis instrument, which is applicable to biological, physical and chemical, cosmetics, health products, food, reagents and other experimental fields.