The present invention relates to the technical field of polyamide materials, and specifically relates to a polyamide sea-island fiber and a process for producing the same and the use thereof. In the polyamide sea-island fiber, the island component is a polyamide resin selected from one of polyamide 56, polyamide 510, polyamide 511, polyamide 512, polyamide 513, polyamide 514, polyamide 515 and polyamide 516, preferably polyamide 56 or polyamide 510; the sea component is one of polyethylene, low-density polyethylene, polystyrene, water-soluble polyesters, polyesters and polyurethanes, preferably polyethylene, low-density polyethylene or water-soluble polyester. The polyamide sea-island fiber of the present invention has better mechanical properties, better softness, good dyeing properties, high grade of dyeing grey scale, high dye uptake, high dyeing depth and high color fastness.