The preparation efficiency and transfer fidelity between different traps are crucial factors limiting the practical application of ultracold atomic systems in quantum precision measurement. This paper presents an integrated solution to address two core issues: insufficient power stability of optical dipole traps during evaporative cooling, and decoherence induced by Majorana transitions during magnetic trap transfer. In the preparation stage, a dual-photodetector based optical power feedback stabilization system was designed and implemented, solving the power control challenge throughout the entire evaporative cooling process (especially in the milliwatt low-power regime) and suppressing power fluctuations below 0.11% during critical phases, thereby achieving efficient evaporative cooling. In the transfer stage, precise control of the bias magnetic field in the quadrupole trap was employed to actively manipulate the position of the magnetic field zero, maintaining a safe distance between the ultracold atomic cloud and the zero point, effectively suppressing atom loss and decoherence caused by Majorana transitions. Experimental results demonstrate that after 6.8 seconds of evaporative cooling, ??Rb ultracold atoms with an atom number of approximately 3×10? and a temperature of 30 nK were successfully prepared and coherently transferred to a quadrupole magnetic trap for stable magnetic levitation. The preparation and transfer methods established in this work provide key technical support for building reliable ultracold atomic sources for high-precision metrological applications such as atom interferometry and quantum gravimetry.