Liquid metal refers to a large class of multi-metal alloy functional materials. It is in a liquid state at room temperature. It can flow, has high boiling point, strong electrical conductivity, and high thermal conductivity. The manufacturing process does not require high-temperature smelting, and is environmentally friendly and non-toxic. In the design process of liquid metal pens, attention should be paid to temperature collection, constant temperature heating control, temperature status indication, and strict control of the temperature of the refill to ensure smooth writing. Compared with liquid metal pens, traditional circuit board production is simpler and more environmentally friendly. In the past, the circuit board was made of copper mold on the substrate material made of silicon and then etched according to the drawing, which not only wasted time and manpower but also polluted the environment. The liquid metal electronic pen can simplify the previous complicated process and easily complete the engraving of the circuit board. This liquid metal electronic pen design is the world's first design that uses liquid metal instead of traditional ink. It can not only write, draw, but also draw circuit diagrams. The drawn circuit also has conductive function and has great practical value in circuit repair, DIY independent circuit design and consumer electronics. Liquid metal electronic pens are often used in flexible circuits, electrical sensors, electronic art, electronic decoration, circuit units, electronic greeting cards, electronic patterns, functional electronic devices, circuit demonstration teaching, self-made circuit boards, repair open circuit boards, etc. In terms of use, the hand-held degree is high and the comfort is strong. A tail plug at the tail of the refill can prevent ink leakage, and a matching pen can be replaced when writing is not smooth. When changing the pen tip, gently throw the pen tip down a few times to write smoothly, thus improving the service life and practicability of the liquid metal pen. Liquid metal electronic pens won the Excellent Product Award and the 2017 Red Star Award at the 18th China International High-tech Achievement Fair.