The paper aims to construct the gradient of the perception ability of elderly users, determine the visual matching range of elderly users in the process of human-computer interface interaction, help elderly users accurately identify user interface information, and provide R&D designers with a parameter basis for aging modification. Older users are often affected by size and quantity when recognizing interface information. By controlling the variables "chart size" and "chart spacing", the elderly's ability to identify and collect page information under 25 combinations is tested, and a comprehensive performance index GP is proposed. Combined with the response time and accuracy of the elderly, when elderly users extract information during human-computer interaction, 1) when the icon spacing is less than twice the distance of the icon size, the side length of the icon is 32 px-48 px, the elderly’s response time shorter; the reaction time will be longer if the side length is less than 32 px; the side length higher than 48 px will be greatly affected by the icon spacing; 2) The visual search ability of the elderly will increase as the icon size increases, and the accuracy rate will increase; 3) When the icon spacing size is greater than 1 times the icon size, GP will show a downward trend when the icon size side length is greater than 40 px. Taking into account the physiological factors of elderly users and other physiological factors, in order to optimize the human-computer interface and improve the recognition accuracy of elderly users, it is recommended that the interface design elements should focus on icon size and icon spacing, and the icon size should not be less than 32 px. The optimal range is 32 px-48 px, the icon spacing should not exceed twice the spacing, and the optimal range is 1 to 2 times.