A signal processing system applicable to an electronic system having a storage unit, an indicator light, and a driving circuit includes a first signal processing unit, a second signal processing unit, and a signal computing unit. The indicator light will light up, if the electronic system does not access the storage unit for data. The first signal processing unit is electrically connected to the driving circuit and configured to receive a first pulse signal while the electronic system is accessing the storage unit for data, charge/discharge and transform the first pulse signal, to output a second pulse signal. The second signal processing unit receives the second pulse signal, charges/discharges and transforms the second pulse signal, to output a third pulse signal. The signal computing unit receives and computes the second and third pulse signals to generate a fourth pulse signal for driving the indicator light to perceivably glitter.