The present invention discloses a boosting and filtering type pulse width modulation power supply based on a beam excitation type logic amplifying circuit. The boosting and filtering type pulse width modulation power supply is characterized by mainly comprising a diode rectifier U, a power amplifier P1, a transformer T, a switch filtering circuit connected in series between the diode rectifier U and the power amplifier P1, a power supply output circuit connected with a secondary side coil L2 of the transformer T and the like. According to the boosting and filtering type pulse width modulation power supply, a voltage in the circuits can be increased and meanwhile, noise waves also can be filtered, so that accuracy of the product can be further improved and the application range of the product is further enlarged; and the beam excitation type logic amplifying circuit is ingeniously applied to the pulse width modulation power supply, and thus, output quality of the power supply can be ensured; a slope equalizer and voltage and current comparators are also ingeniously applied to the circuits of the power supply, so that not only are radio frequency interference of the circuits and external radio frequency interference effectively reduced, but also the circuit structure is greatly simplified, and thus, manufacturing cost and maintenance cost are reduced to a great extent.