The dynamics of inhomogeneous spin textures in ferrimagnetic systems, such as domain walls and magnons, remain incompletely understood. To address this issue, we developed an atomistic model and observed spatially inhomogeneous THz-oscillation dynamics in a ferrimagnetic spin-chain. Our findings reveal that when excited by spin transfer torque, the spin-chain oscillates in the exchange mode with an inhomogeneous profile. Additionally, we propose an anti-parallel exchange length to quantify this inhomogeneity. This work provides new insights into ferrimagnetic spintronics and could help accelerate the development of new technolo-gies that harness the unique properties of ferrimagnetic materials.