The criterion definitions in pedagogical researches are analyzed in the article. The attention is paid to the studying of the future teachers ecological culture formation criterion. Ecological culture in all its aspects and the difficulties of its diagnostics are described. Criteria systems offered by the researchers are considered. The criterion “relationship” usage expediency is substantiated. The criterion has three indicators each of its can be described by seven signs. The combination and degree of the described signs permit to diagnose ecological culture type future teachers rather easily and exactly.