A novel type of large mode area single mode fiber with heterogeneous helical cladding is proposed for 2.0 μm. Based on the coordinate transformation theory and the finite element simulation technology, a two-dimensional simulation model for a three-dimensional helical fiber is established, the mode transmission characteristics of the fiber are analyzed, and the expected conclusions and optimized optical fiber parameters are obtained. The transmission loss of the fundamental mode is less than 0.1 dB/m, the transmission loss of high-order mode is more than 10.0 dB/m, the largest single-mode core diameter is up to 66 μm, and the mode field area is about 2360 μm². When the fiber is bent, the helical slit width is reduced to about 9 μm. When the helix pitch Λ is increased to 26 mm and the minimum bending radius is 33 cm,the transmission loss of fundamental mode is 0.10 dB/m, and the transmission loss of high-order mode is greater than 10.08 dB/m. The proposed fiber has a long helix pitch and all-solid-state structure, parameters can be coordinated with each other, so it is conducive to preparation and use of optical fibers. The mode discrimination ability meets the requirements of large mode area single mode fiber. It is expected to be well applied in high power fiber lasers.