The invention relates to monocrystalline copper, and specifically relates to a method utilizing crystal merging growth to prepare monocrystalline copper strips. Utilization of polycrystalline copper strips which can gradually merge and grow at a sufficiently high temperature, grain boundary areas can be gradually centralized together due to the merging growth process, when the grain boundary areas are large enough or two large enough crystals meet each other, an area which cannot be converted into a monocrystalline is formed; through a method of step-by-step continuous heating, the area which is not converted into the monocrystalline always remains relatively small size, at the same time, the part which is not converted into the monocrystalline is avoided from generating anisotropy by an ultrasonic vibration effect, and a continuous single-crystal strip area is eventually obtained by heating to grow for enough time.