Abstract: The society which is full of differences can barely put an end to all kinds of contradictions,which will naturally give rise to conflicts and struggles as long as the contradictions appear.There are different kinds of struggles in different forms,among which only the just struggle is rational,lawful and morally beneficial,safeguarding the fairness,equality and eventually pushing forward the scientific and sustainable development of our society and social harmony.For this,further knowledge of and understanding the problem of struggles in the course of contradiction are of vital realistic and practical significance.

Key words: contradiction, just struggle, scientific development, social harmony