Bottle beams with different sizes can be used to trap particles at different scales. A new method of changing the size of bottle beam using a popular sphere lens telescope system is proposed. The analysis is based on the geometrical optics, and simulated by ray tracing with optical design software ZEMAX. The bottle beams were captured and measured before and after the telescope system. It is shown that the size conversion ratio of bottle beam corresponds to the ratio of focal length of the two lens (magnification of the telescope). The theoretic analysis and numerical stimulation agree well with the experimental results.