Heat insulation and cold insulation method of liquefied gas low-temperature tank

The invention discloses a heat insulation and cold insulation method of a liquefied gas low-temperature tank. Insulation plates with joggling structures are connected with each other in a joggled manner; a whole insulation structure is formed on the surfaces of tanks; all the insulation plates are fixedly connected with the tanks through fixed brackets; and the tanks are correspondingly provided with bolts in threaded connection with the fixed brackets. The joggled surfaces of the insulation plates are sealed by using hard polyurethane foam plastics in an injection foaming manner; and the outer surfaces of the joints are sealed by silica gel. The insulation plates include a first insulation layer, a second insulation layer and a third insulation layer arranged in sequence; the three insulation layers are arranged in a staggered manner; the joggling structures are formed on all four side surfaces; the adjacent insulation layers are connected in a bonding manner through low-temperature glue; and an outer protection layer is arranged on the upper surface of the first insulation layer. The method has the advantages of wide application range, safety, reliability, excellent closing performance and convenience for safety maintenance.