[Objectives]  The author explored the large-scale geographical variation in the frequency of intermittent outbreaks of the beet armyworm, Spodoptera exigua (Hübner) inChina, in order to determine the causes of outbreaks. [Methods]  This was done by analysis of the characteristics of administrative regions, including latitude and longitude, within the geographical distribution of 121 large-scale outbreaks of beet armyworm which occurred in the 52 year period from 1956 to 2008. [Results]  Records from each administrative region indicate that outbreaks occurred in 17 provinces or municipalities. These were divided into 3 groups based on the frequencies of outbreaks they experienced: low frequency (1 to 4 outbreaks), regular (5 to 9) and high frequency (10 or more). The number of outbreaks experienced in low outbreak frequency regions were1 ineach of Tianjing,Beijing, Hainan andHunan,2 inYunnanand3 ineach ofGuangxi,LiaoningandFujian. The numbers of outbreaks in regular outbreak frequency regions were5 inHubei,7 inAnhuiand8 ineach ofShanghai,JiangxiandShanxi. The regular outbreak frequency regions accounted for 29.8 percent of total outbreaks. The numbers of outbreaks in the high outbreak frequency regions were10 inShandong, 13 each inHenanandZhejiangand34 inJiangsu, together accounting for 58 percent of total outbreaks. Outbreaks occurred across latitudes 21.44°-41.97°N, from Putian inFujianProvincetoFushuninLiaoningprovince. The latitude range of the most frequent outbreaks was 28°–38°N, where almost 89.3 percent of outbreaks occurred. The range of longitudes in which outbreaks occurred was from 107.09° to 123.97°E, which is from Guangzhong inShanxitoFushuninLiaoningprovince. The longitude range of the most frequent outbreaks was 113°-121°E, in which around 81.8 percent of outbreaks occurred. [Conclusion]  The major outbreak region was the Huabei Plain and the middle and lower reaches of theYangtze River. The main outbreak hosts were vegetables and cotton, and the outbreak season was from July to October. The main geographical feature of high outbreak frequency areas was low altitude; that is, an average altitude of less than 500 m (a very small proportion of outbreaks occurred in a basin with an average altitude of 1 000-2000 m). Climatic characteristics of this area include a temperature range from warm temperate (3400℃≤active accumulated temperature≤4500℃) to subtropical (4500℃≤active accumulated temperature≤8000℃), and moisture range from moist (annual precipitation≥800 mm) to sub-humid (400 mm≤annual precipitation≤800 mm). High outbreak areas had sub-tropical and temperate monsoon climate zones with hot, rainy summers and cold, dry winters.