Abstract: In this paper, author puts forward the different opinions on some principal theoretical problems in "Assumption on establishing the characteristic parameters of the plant flora" (See "Journal of Wuhan Botanical Research" , 1989; 7(1): 49—54).1. How to understand the concept of flora is a basic problem, Author thinks this problem must be analysed and discussed according to two aspects of the intrinsic features of plant species and the plant phylogenetic principles judging from the theory of plant evolution. We advance a new concept on flora as follows: FLORA is the sum of the all phytotaxonomic units (such as species, or genera or families and so forth)in some (geological) period in a physiographical area(or administrative region); It is the time and space outcomes of the evolution and breeding, origination and development and unceasingly dilation of the plantae in the integrative action of the longterm natural geography conditions(especially the paleogeographical conditions), especially the unity of opposites on the genetics and variatin of plant species(or population); It has gone through the innumerable evolutionary processes from the plant taxa being devoid, little, simple and low-grade to possession, many, complex and high-grade of those; Last, it has formed the organic entity(or system)of the dialectical unity which are the mutual contace also mutual different and consecution also inconsecution in level(geographical)and vertical distribution of every phytotaxonomic units, floristic constitution and combination and it's historical development processes; It is a statical system also a dynamical one.2. Author thinks the whole classificational systems of plant in new published have not expressed the affinitical relationships among the plant taxa and their evolutionary sequences, and the affinitical relationships among the plant taxa are not the simple double-dimensional linearly relationship, but are the complex poiydimensional space relationships. So, the different floristie elements of the families in a flora cann't arrange to accumulate and add in accordance with the arrangement's sequence of the families in some classificational system of plants.3. Author thinks the fundamental characteristics of flora can be divided into the phytotaxonomic and phytogeographical characteristics. The former includes the floristic abundance, resemblance, ancientness and growth of speciation, the later includes the complex and endemicity of floristic elements. So, the quantitative expression of the fundamental characteristics of flora only includes the relative rich degree, relative ancient degree and relative endemic degree which is a one-sided view.