A method for performing uplink traffic shaping of an electronic device and an associated apparatus are provided, where the method includes the steps of: monitoring at least one modulator-demodulator (modem) state of a radio modem of the electronic device; and according to the at least one modem state and according to at least one uplink traffic gating strategy, dynamically controlling whether to allow uplink traffic to pass through the radio modem, and more particularly, in a situation an alarm-aware uplink traffic gating strategy is involved, determining whether a time interval between a wake-up type alarm trigger and a last time point when uplink traffic is previously allowed because of another alarm trigger reaches a predetermined alarm-triggered gate open threshold; and controlling whether to allow uplink traffic to pass through the radio modem according to whether the time interval reaches the predetermined alarm-triggered gate open threshold.