The step by step seeding approach for preparation of gold nanoflowers was investigated systematically,in which 20 nm gold nanoparticles were used as the seeds and a mixture of HAuCl4 and ascorbic acid as growth solution.In this seeding approach,ascorbic acid promoted the rapid reduction of HAuCl4 and the rapid formation of small Au particles in the growth solution.The attachment of the small particles on the seed surface contributed to the growth of the nanoflowers.Ascorbic acid promoted the rapid reduction of HAuCl4 in this seeding approach.In the first two steps，the size of the seeds increased with isotropic growth,and in the last two steps,some branches on the seeds surface grew through the secondary nucleation.Finally,a uniform and controllable gold nanoflower formed by this seeding method.Gold nanoflower showed good properties on the surface enhanced fluorescence spectroscopy due to its larger surface roughness and special electromagnetic fields of the branch.