Unlike the abundant history-oriented researches on Guan Yin belief in Macao, the current paper adopts the ethnographic approach with an emic view to study the most popular religious belief in Macao. This study by examined closely to the most common worshipping rituals of Guan Yin believers in Macao to see if they influences on Macao society and inversely, if the rituals and custom are transformed along with the changes of Macao society, and if the changes on generation, gender, and economy related to the transformation. It is found out in the study that the Guan Yin belief and the rituals in Macao basically follow the customs from the Lingnan district in southern China, but with the grace of freedom of religions, the Guan Yin belief rituals are also enriched by absorbing local culture characteristics, say, Confucianism, gender hierarchy, materialism, etc. And the simplifying rituals and the transforming Guan Yin community can also be regarded as the manifestation of current social structures and cultural values.