The invention discloses an amplifying and filtering circuit-based soft start power supply circuit. The soft start power supply circuit is characterized by mainly comprising a driving chip IC, a resistor R5, a resistor R7, a capacitor C3, a capacitor C4, a diode D3, a soft start circuit, an amplifying and filtering circuit, a dual-polarity buffer circuit and a time-delay driving circuit. The driving chip IC disclosed in the invention adopts an NE555 integrated chip which is combined with a peripheral circuit, so that soft start of an electronic product can be realized; after the power supply circuit disclosed in the invention is connected with a power supply, the output voltage has a starting process and is increased at a relatively slow speed to a set value so as to protect the electronicproduct from surge impact; and meanwhile, the maximum time delay of about 30 seconds also can be ensured, so that the soft start power supply circuit is suitable for popularization and use.