Ｒainbow and secondary rainbow are magical natural phenomena in the atmosphere． In order to visually observe the rainbow and secondary rainbow and explore their optical phenomena and influencing factors，we designed two demonstration devices for reproducing the rainbow and secondary rainbow，which can reproduce the phenomenon of the rainbow and secondary rainbow at the same time，measure the observation position and the incidence of the rainbow and secondary rainbow．The angle of light，explore the reasons and conditions of the formation of rainbow and secondary rainbow phenomenon． Through the observation and analysis of the rainbow and secondary rainbow produced by transparent glass balls with different diameters，it is indirectly proved that the larger the raindrop，the more significant the rainbow and secondary rainbow phenomenon，and the exit angle of the rainbow and secondary rainbow has nothing to do with the diameter of the water drop．The rainbow and secondary rainbow demonstration device has simple operation，clear phenomenon and low cost．It is very suitable to extend to classrooms or science and technology museums to help understand the rainbow phenomenon and its optical principles．