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利用常规探空和地面观测资料,分析了2000-2009年夏季（6-8月）青藏高原（下称高原）地区雷暴的时空分布特征以及雷暴天气各要素的垂直廓线特征,在此基础上,修正了K指数,并对修正后的K指数（KM）进行了检验。结果表明,高原雷暴中心主要发生在高原西南侧的日喀则、高原中部腹地那曲、拉萨一带以及高原东部地区,夏季高原中部雷暴中心区随月份向西南转移,其东侧的雷暴中心区随月份向南偏移,雷暴中心位置向南偏移且雷暴的月平均频数减少,高原上由南向北雷暴发生的时段不同,高原中部和北部的那曲、沱沱河雷暴峰值的出现时段比南部的拉萨早3～6h;高原南部的定日和拉萨雷暴日大气低层存在逆湿现象。高原地区雷暴日500～400hPa之间为不稳定层,400hPa以上为稳定层,400hPa处假相当位温为最小值,雷暴日平均风向为西南风;对KM指数检验表明,大多数雷暴日KM〉10℃,占总雷暴日的92.7%;当KM〈0℃时几乎无雷暴发生,KM指数对雷暴具有一定的指示意义。“,”Using the routing sounding and surface observation data,the spatial-temporal distributions and isometeoric vertical profiles on thunderstorms weather over the Tibetan Plateau are analyzed in summer(from June to August)during 2000-2009.The stability index Kis modified as KMindex basis on these research and KMindex is validated.The results show that the center of thunderstorm number is mainly located in hinterland,southwest and east over the Tibetan Plateau.The center of thunderstorm number transfer along with months of summer from midland to southwest.The location of thunderstorm center is excursion to south and the mean frequency of thunderstorm numbers decrease in recently 5years.The thunderstorm happened in different time over the Tibetan Plateau.The occurring time of thunderstorm in north and midland is 3~6hearly than that in the south of Tibetan Plateau.The inverse humidity occurs near ground in Lasa and Dingri district.There is the minimum value ofθseon 400hPa.In addition,an especially unstable layer is present between 500and 400hPa,and above 400hPa,the condition of atmosphere is stable.The validate KMindex is shown that approximately 93.5%of thunderstorm occur with the KM10℃ and there is no thunderstorm occur when KM0 ℃.The KMindex can predict thunderstorm on the Tibetan Plateau combined with wind,humidity and other parameters.