The BP4000 high-precision bio-printer utilizes advanced droplet control technology for precise cell printing, achieving single-cell printing control within droplets. By inoculating a quantitative array of cell colonies on a suitable ECM surface (such as the matrix Matrigel), after a certain period of 3D cell culture, these cell colonies can grow into uniform-sized standardized cell arrays on the ECM surface. According to the user's construction needs, the BP 4000 high-precision bio-printer can adjust the size and number of cell colonies, thereby controlling the diameter size of the resulting 3D cell spheres and the number of microspheres.