In this work the macromolecular chain’s conformations in dilute

semidilute

concentrated and extra concentrated polymer solutions were discussed respectively

at the same time the interactions between macromolecules

the complex correlative effects and the changes of macromolecular sizes were explained in detail

and the definition of excluded volume and several concepts: thermic correlation

long-range correlation and full Gaussian concentration were introduced. It is indicated that the conformations at different chain’s size ranges are different in the solutions of different concentrations

and that the single chain’s size happened contraction in lytrooic condensation process of macromolecules

from Flory size R

F

to unperturbed chain dimension R

0

. This is a specialty of lytrooic condensation of macromolecules.