Phytoliths, also called amorphous silica particles, have a great geochemical stability and could occlude a certain amount of organic carbon during the forming process. At present, phytolith-occluded carbon (PhytOC) is recognized as one of long-term stable carbon sequestration mechanisms and has significant influence on regulating global climate change. At the same time, PhytOC isotope research has great value for paleo-environment, paleo-climate reconstruction and other fields. Therefore, more scholars pay attention to the PhytOC geochemical research. Based on the current research status, we summarized the current state of understading about phytolith forming process, elemental composition, geochemical stability, PhytOC sink and PhytOC isotope application for paleo-environment reconstruction. We also summarized the main problems of geochemical research on phytolith and PhytOC, which will make great contribution to further research on phytolith geochemical research.