In this paper, several misunderstandings over plant nutrition theory and fertilization practice in agricultural production in China had been analyzed. One is the misunderstanding over the classification of essential nutrients for plants. The second is the misunderstanding over the sources of plant carbon, hydrogen and oxygen elements. The third is the misunderstanding over the importance of production of essential nutrients for plants. And the fourth is the misunderstanding over the evaluation of chemical fertilizer and organic fertilizer efficacies. Regarding the production problems caused by those misunderstandings, a four-level classification of plant essential nutrients and solutions such as development of anaerobic compost are proposed.