The paper aims to analyze the rationality of the interactive design of the smart TV interface and the feasibility of eye tracking in the evaluation of the usability of the TV interface. The usability evaluation method combining subjective and objective is adopted to evaluate and optimize the interface design of smart TV. Taking the TCL-V7300 smart TV as the research object, 45 subjects are tested with the Tobii X120 eye tracker, which is divided into two test phases:free browsing interface and user task test. Objective usability evaluation uses eye movement indicators (gaze hotspots, AOI first gaze time, AOI gaze rate, gaze trajectory) and behavior indicators (task completion time, task success rate) based on eye tracking to analyze objective results; subjective usability evaluation through user interviews to obtain the participants' understanding and experience of using the test points. Finally, in view of the usability problem of smart TV interface interaction, the interface optimization design and effect evaluation are carried out. The subjective and objective usability evaluation test conforms to the design principle of eye tracking experiment, and it is a universally applicable usability evaluation method for the design of smart TV interactive interface.