A heat insulation construction process for a liquefied petroleum gas low-temperature conveying pipeline comprises indoor pre-heat-insulation and outdoor heat insulation. Indoor pre-heat-insulation construction comprises the steps that firstly, a shear key is arranged on the pipeline; secondly, elastic needle-like glass felts are arranged on the two sides of the shear key and fixed; thirdly, the elastic needle-like glass felts are wound by a first glass cloth layer and fixation is carried out; fourthly, a polyurethane foam heat insulation layer is sprayed; fifthly, a glass fiber reinforced plastic protective layer is sprayed and formed; sixthly, end portion sealing is carried out, and the spraying pre-heat-insulation work is completed; and seventhly, an end portion pipe cap is installed. Outdoor heat insulation construction comprises the steps that firstly, foam tiles are installed; secondly, a waterproof aluminum foil layer is arranged; thirdly, a tee joint, a bend, a support pipe base and a valve heat insulation part are installed; fourthly, heat insulation is carried out at the position of a welded junction on spot; fifthly, an outer protective layer is arranged; and seventhly, end portion protection is carried out. By means of the heat insulation construction process, all pipelines can be subjected to tight heat insulation, and the heat insulation effect is greatly improved; and moreover, the heat insulation construction process cannot be affected by the weather, and the heat insulation problem of the liquefied petroleum gas low-temperature conveying pipeline is solved.