Experiment study on surface coloring of 304 stainless steel is carried out by using picosecond laser. The mechanism of the coloring on stainless steel surface by picosecond laser is analyzed, and the surface color model is established. The influence of the laser processing parameters such as scanning line spacing, scanning speed and pulse energy on coloring effect is studied，respectively. Experimental results show that changes of line spacing, scanning speed and pulse energy have a significant impact on the coloring effect，and good color can be obtained with the parameters range of scanning speed from 90 μm/s to 300 μm/s, line spacing from 0.001 mm to 0.01 mm, and single pulse energy from 60 mJ/cm2 to 140 mJ/cm2. The effects of three parameters on coloring have similar impact. Based on the experiment, the relationship between the parameters of picosecond laser and the CIE L*a*b* color model is obtained. Finally, the color aging contrast test of the samples after coloring is carried out. Experimental results show that the chromatic aberrations ΔE of laser coloring samples with different aging times are very small, which indicate that all samples are very similar. And they have good anti-aging effect.