The invention discloses a device and a method for detecting penetration of hammering piling for a steel pipe pile. The device comprises a pile hammer installed at the top of the steel pipe pile, a blow count sensor installed on the side of the pile hammer, a light reflection film installed at the upper end of the pile hammer, laser ranging devices located right above the light reflection film and a computer. Three laser ranging devices are provided, each laser ranging device is composed of a laser range finder and a G-sensor located on the upper portion of the laser range finder, and the laser range finder is connected with a computer in a wireless mode. By means of the device and the method, detection of the penetration in the steel pipe pile piling process is achieved and is compared with the preset value of a computer control system. When the penetration is too small, hammering stop signals are transmitted automatically, pile damage, hammer damage and the like caused by the fact that the penetration is too low are reduced, steel pipe pile piling construction is guided, construction efficiency is improved, and meanwhile quality control in the steel pipe pile piling process is improved.