The combustion characteristics of premixed rich CH4/O2 in micro channel was investigated experimentally via the visual micro-scale combustion test bench. The flammability limits, flame behaviors, stability limits and flame propagation speed were researched by changing the combustor sizes and inlet flow rates. The results show that there are three flame behaviors observed in the experiment, respectively external flame at the exit, stable flame in the channel, flame with repetitive extinction and ignition (FREI). Stable combustion zone increases with the increase of CH4 inlet flow rate. But the stability of the flame at high velocity may not be increased when the inlet flow rate is increased. The flammability limit was greater when the channel height was larger. Meanwhile, the increasing height and the decreasing length of the channel were also beneficial to stability limits in the channel with a certain range of equivalence ratios of 1.25 - 1.80. This experimental study on the combustion characteristics of premixed rich CH4/O2 in micro planar channels provides support for micro combustion in the future.