A nanoflower structure is fabricated on the silver film by a focused 1 kHz femtosecond laser irradiation. By controlling the laser irradiation parameters such as pulse energy, number of pulses and out-of-focus distance, a series of silver nanostructures with respective characteristics are produced. According to the optics and scanning electron microscope (SEM) observations, the formation process of silver nanoflower should be due to the combination of femtosecond laser ablation and successively solidified flow dynamics in molten material. Besides, a possible interference modulation between the incident light field and the induced surface plasmon wave also can be responsible for the formation of silver nanoflower. In the application, the irradiated silver film showed strong surface enhanced Raman scattering (SERS) effect after soaked in R6G solution.