The present invention relates to an alkynyl-substituted heterocyclic compound acting as an FGFR inhibitor, a preparation method therefor and the medical use thereof. In particular, the present invention relates to a compound as shown in general formula (I) and a pharmaceutically acceptable salt thereof; a pharmaceutical composition including the compound or a pharmaceutically acceptable salt thereof; a method for treating and/or preventing FGFR-associated diseases, particularly tumours, by using the compound or a pharmaceutically acceptable salt thereof; and a preparation method for the compound or a pharmaceutically acceptable salt thereof. The present invention also relates to the use of the compound or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition including the compound or a pharmaceutically acceptable salt thereof in the preparation of a drug for treating and/or preventing FGFR-associated diseases, particularly tumours, wherein the definition of each substituent in general formula (I) is the same as that in the description.