The invention discloses an environment-friendly soft heat-insulating toilet seat and a manufacturing process thereof. On one hand, the environment-friendly soft heat-insulating toilet seat comprises a plastic seat frame which is made of original plastic grains, wherein the plastic seat frame is provided with a plurality of reinforcing ribs; a plurality of adhesion holes are formed at the periphery of the plastic seat frame; a polyurethane (PU) layer is wrapped outside the plastic seat frame through PU material foam molding; and the PU layer also passes through the adhesion holes to be tightly adsorbed to the plastic seat frame. On the other hand, the manufacturing process of the environment-friendly soft heat-insulating toilet seat comprises the following steps of: 2.1, preparing the original plastic grains into plastic grains, preparing the plastic seat frame by high-temperature high-pressure injection molding, taking the plastic seat frame out after the plastic seat frame is cooled; and 2.2, filling PU material into the plastic seat frame in the step 2.1 to form the toilet seat by foam molding. The toilet seat has the advantages of softness, comfortable seat feeling, heat preservation, safety and environmental friendliness and the like, and is easy to wash and keep clean.