In order to reduce the problem of inter-mode crosstalk in the low-mode fiber, a new type of dual coupling ring assisted few-mode fiber structure design is proposed, the main influencing factors of crosstalk in the 6-LP mode are analyzed, and five main structural parameters of the new dual coupling ring structure are simulated and analyzed. Based on this designed structure, a 6-LP few-mode fiber is developed, which reduces the inter-mode crosstalk in the few-mode fiber. The results show that in the 6-LP few-mode fiber, the effective mode refractive index difference between the LP₂₁ mode and the LP₀₂ mode is the closest, and the difference is the main factor affecting crosstalk. The double coupling ring structure adjusts the effective mode refractive indices of the LP₂₁ mode and the LP₀₂ mode. In this structure, the minimum refractive index difference between LP₂₁ and LP₀₂ is 1.5×10^-3, which is 1.88 times the minimum refractive index difference of the traditional step structure under the same conditions.