We designed and fabricated a 2×2 channel multi-mode interference-Mach-Zehnder interferometer polymer thermo-optic switch. The thermo-optic switch comprises a borosilicate glass substrate, a core layer of JA-206, and an upper cladding layer of RZJ-390. The performance of this thermo-optic switch was simulated using the finite-difference beam propagation method and finite element method, and the results show that the switch is characterized by low power consumption and higher extinction ratio (ER). Furthermore, this study utilized a femtosecond laser to investigate the optimal preparation parameters. The results indicated that setting the laser power at 1 mW and the scanning speed at 4 mm/s ensures an efficient manufacturing process. With the operating wavelength of 1550 nm, the tests show that the driving power of the thermo-optic switch is about 5.5 mW, and the ER reaches 23.37 dB. In addition, after a continuous test lasting 12 h, the rise and fall times of the switch were measured to be <1.7 ms. Therefore, it meets the optical interconnection requirements of electro-optical printed circuit boards.