The invention relates to a gas preprocessing method applied to analytical instruments, which comprises the following steps of: a, providing at least two paths of processing channels; b, allowing gas to be processed to enter at least one path of processing channel for processing; c, introducing part of processed gas into the downstream of the processing channels, and introducing part of gas into at least one path of the processing channel which does not perform gas processing to make the processing channel become a regenerative processing channel; d, monitoring the processed gas; and e, according to a monitoring result and a set value, judging whether the processing channel through which the gas to be processed passes is needed to be adjusted or not, if so, adjusting the processing channel through which the gas to be processed passes, and returning to the step b, and otherwise, returning to the step d. The invention also provides a gas preprocessing device for implementing the method. The gas preprocessing method and the gas preprocessing device have the advantages of capability of performing gas processing continuously, long service life, little maintenance and the like.