The invention provides a method for analyzing yield reduction reasons of a condensate gas well. The method is characterized by comprising the following steps: step 1, evaluating the yield increase potential of a target well, and judging the yield reduction reason; and step 2, if the descending reason is caused by the descending of the flow capacity of the underground fluid, analyzing the descending reason of the flow capacity of the underground fluid by establishing a database of mineral product data, production parameter changes and indoor experimental analysis. Combining the change conditionof production parameters with experimental analysis data, and determining four types of blocking modes causing the decrease of the flow capacity of underground fluid, namely solid-phase blocking froman underground pressure gauge to a wellhead, liquid-phase blocking from the underground pressure gauge to the wellhead, solid-phase blocking from the underground pressure gauge to a stratum, and liquid-phase blocking from the underground pressure gauge to the stratum. The method has the advantages that the field operability is realized, the practicability is higher, and a field engineer can compare actual production data change with options in a database conveniently, so that the reason of yield reduction of the target well is determined quickly.