The invention relates to an atmospheric automatic monitoring apparatus capable of realizing sampling/calibrating alternative equivalent operation, and a method thereof. An air path center system is arranged, a standard gas introduction mode during apparatus calibration is improved, and a relay connects a dynamic calibrator, a solenoid valve and a sampling pump; when calibration is carried out, the dynamic calibrator is started, and the solenoid valve and the sampling pump are closed through powering off the relay; and when sampling is carried out, the dynamic calibrator is closed, and the solenoid valve and the sampling pump are started through powering on the relay in order to realize the alternative equivalent operation process of calibrating/sampling. An air acquisition system is a sampling head, a standard gas generation system comprises a standard gas tank, a zero gas generator and the dynamic calibrator, the air path center system comprises an air path center channel, an intelligent transition control system comprises the sampling pump, the solenoid valve and the relay, a temperature control device comprises a humiture probe and asensor, a humiture controller and a heat insulation cover, and a pollutant analysis system comprises a plurality of filtering devices and an analyzer.