A method for physiological measurement and a portable electronic device adapted for executing the method. The portable electronic device includes a button and a display. The method for physiological measurement includes the following steps: transmitting at least one trigger signal when the button is pressed transmitting a first optical signal towards the outside of the button through the button according to the trigger signal receiving a second optical signal through the button and obtaining physiological information according to the second optical signal, in which the second optical signal is an optical signal that is reflected when the first optical signal encounters an object.
