<p>Liquid metal, which has the advantages of high conductivity, fluid morphology at room temperature, excellent ductility and plasticity, has been widely used as electrodes or functional structures in flexible electronics. The existing flexible functional components are mostly flexible hybrid electronics, that is, the substrate is flexible and the functional components are rigid. In order to ensure the long-term stable operation of devices, the reliable encapsulation of liquid metal and traditional rigid components (such as wires, pins, etc.) and the prevention of liquid metal leakage are the key steps for the preparation of liquid metal based flexible electronics. In this paper, the liquid metal and rigid components are encapsulated based on the strong adhesive interface characteristics of the addition polymerization of ethyl α-cyanoacrylate under the catalysis of water. Taking the liquid metal encapsulation in 3D printing acrylamide hydrogel flexible substrate as an example, the effects of ethyl α-cyanoacrylate on the bonding strength of hydrogel, the peel strength of copper wire and the encapsulation performance were studied. The results showed that the bond breaking stress of ethyl α-cyanoacrylate was more than 200&#xa0;kPa, and the peel strength was more than 160&#xa0;N/m. Lastly, taking the liquid metal strain sensor as the application object, the reliability of ethyl α-cyanoacrylate encapsulation was demonstrated. This study provides a guarantee for the reliable operation of flexible electronic devices based on liquid metal.</p>