The invention relates to a preparation method of a liquid smoked longsnout catfish soft can, pertaining to the technical field of aquatic product processing. In the invention, a channel catfish is taken as a raw material, and the finished liquid smoked longsnout catfish soft can is prepared through pretreatment, deboning and skinning, rinsing, draining, fishy smell removing, draining, liquid smoking, rinsing, drying, ripe preparing, vacuum packaging, sterilizing and cooling. The adoption of the channel catfish as the raw material for preparing the liquid smoked longsnout catfish soft can is very beneficial to elevating the processing level of leftovers of agricultural, livestock and aquatic products in China and can produce great economic benefit.