The plant communities in Foping Natural Reserve were explored in this study.The diversity index and Huffman coding were used to examine the diversity and complexity of plant communities,as well as the relationship between complexity and species diversity.The results showed that:(1)The species diversity and complexity of plant communities presented a “low-high-low” pattern of skewed normal distribution as the altitude increased.The largest region of total complexity and diversity of plant community was concentrated from 1 300 to 1 500 m.The change pattern of total complexity and disorder complexity with altitude was similar to species diversity of communities (“low-high-low” pattern).However,the structure complexity had no regularity while the altitude increased.(2)Plant species diversity in the natural reserve was not only related with the altitude change,but also had close relationship with density of Bashania fargesii and Fargesia qinlingensis.The species diversity and species number significantly increased in the intersection of two bamboo groves.(3)The total complexity and disorder complexity of plant community had significant linear relations with the each index of species diversity,respectively.The variation of species diversity can totally express the changes of plant community complexity but can not be used to measure the structure complexity,because there is no significant correlation between species diversity and structure complexity.