The invention provides a speed planning method, a system, a control system, a robot, and a storage medium. The method comprises the following steps: establishing a track model according to chronological order and setting a constraint condition, wherein the track model comprises an end track, and at least one of final motion parameters corresponding to the the end track is non-zero; according to the track model, establishing a speed planning curve model; and based on the speed planning curve model and according to the constraint condition, calculating optimal motion parameters by using an optimal time as a target; obtaining a target speed planning curve based on the optimal motion parameters. According to the invention, first, speed planning can be performed on a path segment in any start or end state without being limited by start or end parameter values of the path segment; furthermore, all branch paths can be covered in an S-type acceleration and deceleration process, so that the application range is greatly broadened; and finally, according to the speed planning method provided by the invention, whether the speed is first constrained or the acceleration is first constrained doesnot need to be distinguished, thereby greatly simplifying a modeling process and helping a user to improve work efficiency.