At present, the process of calculating the orbits and orbital velocities of celestial bodies involves many advanced mathematical concepts and physical principles, which are rather difficult for teenagers to understand. To facilitate a deeper understanding of celestial motion, this article uses conic sections and their properties, which are easier to understand, to discuss and calculate the orbital equations and orbital velocities of celestial bodies. A concise formula for orbital velocity is derived. Moreover, compared with non-purely theoretical calculation methods, it not only provides a more precise description of the calculation process but also summarizes the motion situations under all velocity ranges, demonstrating the importance of mathematics in physics. It is hoped that this will inspire teenagers' love for physics.