The composition of n-alkanes and their carbon and hydrogen isotopes in grasses, reeds and tree leaves from five regions with latitudes of 22o to 39o and different temperature in China were measured by using GC-MS and GC-TC-IRMS in order to understand the relationship between n-alkane compositions and their carbon and hydrogen isotopes and the environments. The distribution of n-alkanes in the samples ranges from C15 to C35 with a high odd over even predominance and carbon-number maxima at C27, C29 or C31. The CPI values are from 3.49 to 17.25, and the mean values show a characteristic of tree leaf > reed > grass. The ACL values are between 26.24 and 30.26 and the mean values exhibit a trend of grass > reed > tree leaf. It is observed that Cmax, CPI and ACL values of n-alkanes in the studied plants decrease with increasing latitude and decreasing mean annual air temperature. The δ13C values of C27 and C29 n-alkanes in the plants ranges from –25.3 to –35.5‰ and the grass has a lighter mean carbon isotopic composition than the reed and tree leaf. TheδD values of C27 and C29 n-alkanes in the plants are between –132.1 and –192.6‰ and the mean hydrogen isotopic compositions of C27 and C29 n-alkanes in the grass are lighter than those in the reed and tree leaves. The δD values of C27 and C29 n-alkanes in the gasses and tree leaves from these studied regions are correlated clearly negatively with latitude and positively with air temperature, indicating that these values can be used as indicators of the environments.