Chlorophyll is one of the most significant biochemical parameters for evaluating crop status. It can be used as an index of photosynthetic potential as well as crop productivity. Crop chlorophyll content has been widely used in identifying crop growth condition, physiological status and health. Crop growth condition monitoring and prediction of crop optimal harvest date are both important to the crop final yield. Crop growth monitoring help farmer take measures in time when the crop is suffering from insect pest, plant diseases or meteorological stress. And yield loss occurs if harvest is implemented either in too earlier or delayed time, both of which are undesirable. In this paper, based on the inversion of crop chlorophyll content, we tested the application of crop chlorophyll content in crop growth monitoring and prediction of crop optimal harvest date, proposing new methods. In crop growth monitoring, we took both the individual and group crop condition into consideration, explored different monitoring indexes of them, including crop chlorophyll content and leaf area index. Then the comprehensive assessment of crop growth condition could be implemented by combining these two indices. In crop optimal harvest date prediction,  leaf and stem water content decreasing as crop reached maturity, the color of leaves gradually turning to yellow, a decrease occurs in crop chlorophyll content. Optimal harvest date was predicted by analyzing the change of crop chlorophyll content with temporal variation of harvest yield. Different crop has different characteristics and we used different methods to predict soybean and corn optimal harvest date. The prediction result has been validated to be reliable. The abstract is often the only part of the paper to be read, so include your major findings in a useful and concise manner. Include a problem statement, objectives, brief methods, quantitative results, and the significance of your findings.