A method for controlling an electronic scale in disclosed in this disclosure, which is applied to measure and indicate a state of an external force, comprises the following steps. A weight sensor detects the external force, and a controller drives a prompting device to emit a first light with a first optical characteristic when the external force detected by the weight sensor reaches a first weight. The controller drives the prompting device to emit a second light with a second optical characteristic when the prompting device emits the first light for a predetermined period, wherein the prompting device continuously emits the second light until the external force reaches a second weight.