This paper proposes a dispersion-reconfigurable reflection-type phaser based on PIN-diode loaded stepped-impedance microstrip line. By configuring ‘ON’ and ‘OFF’ states of PIN-diode, the proposed phaser exhibits positive-slope, negative-slope, and zero-slope linearly dispersive group delay responses.  For proof-of-concept demonstration, we use line connection/disconnection to mimic ON/OFF states of PIN diode. Three prototypes are hence fabricated to represent the three different states. The experimental results agree well with the expected responses, which finally validate the proposed concept.