Abstract: Eye-protective alarm. When a user reads, writes or keys with a computer, the photosensitive resistor of the alarm can sense the illumination of the environment and detect insufficient safe visual distance and even detect too long working time and in time emit a warning music to inform the user of these situations. The eye-protective alarm includes a circuit structure including a system processor, illumination sensor, weak current detector, time controller, alarm informing circuit, light indicator module and several switches which are serially connected. The circuit structure via wires is connected to a cell box, an AC power socket and a distance sensor. The photosensitive resistor detects whether the illumination of the environment, safe visual distance and working time meet the preset standard values. If not, the system controller triggers the light indicator module and the alarm informing circuit to play the warning music so as to remind the user to improve these situations.