The invention discloses an environment-friendly convenient decorating pen, comprising a pen tube, a pen point and a liquid outlet control component, wherein two ends of the pen tube are open, and the lower end of the pen tube is communicated with the pen point through the liquid outlet control component. The decorating pen also comprises a grinding part connected to the opening part in the upper end of the pen tube and used for grinding colored foodstuff to produce pigment liquid which can enter an inner cavity of the pen tube. The decorating pen has the advantages that the edible foodstuff can be ground and juiced, and furthermore, the pasty foodstuff or the pigment liquid can be used for decorating pastries through drawing. With the decorating pen, edible fresh plants can be directly taken as raw materials to write and draw on food, so that troubles of preparing pigments in advance are reduced, and especially, the writing and drawing on food become easy and cheap, people do not need to seek cheap pigments for drawing on food, and thus the food with drawings is environmentally friendly and safe. The decorating pen serves as a simple, convenient, safe, environment-friendly and cheap tool for writing and drawing on food.