Development of low-cost, portable and sensitive microdevices for identification of various sample are demanding in various practical applications . To fulfil the demand of multi-parameter sensing, on-chip whispering-gallery-mode (WGM) microcavity sensor array has attracted lots of research interest . However, it remains a challenge to rapidly fabricate arrays of polymer WGM microcavities and integrate with functional materials for sensing applications. Here, we demonstrate the fabrication of WGM laser array by using an optical μ-printing technology [3,4]. The technology enables rapid printing of polymer mushroom-like WGM microcavities and integration with a gain layer and a humidity sensing layer for relative humidity (RH) sensing.