In this paper, some fundamental theories of the Pythagorean interval 2‐tuple linguistic numbers (PI2TLNs) combined with the EDAS (evaluation based on distance from average solution) method are proposed. Firstly, we introduced the original concepts of Pythagorean interval 2‐tuple linguistic sets (PI2TLSs), and two aggregation operators of PI2TLN were also introduced. Then, the steps of the EDAS method were described briefly. Moreover, the PI2TLN‐EDAS model was provided to address the multiattribute group decision‐making (MAGDM) problem, and calculation steps were deduced in detail. The effectiveness of the method was illustrated by taking the ship navigation environment safety assessment as an example. Finally, we conducted comparative analysis between PI2TLN‐EDAS method and Pythagorean interval 2‐tuple linguistic weighted averaging (PI2TLWA) operator/Pythagorean interval 2‐tuple linguistic weighted geometric (PI2TLWG) operator.