Kammala wannan jumlar: Bayan Yaƙin Opium na Farko da kuma kafa Hong Kong, Macau ya rasa matsayinsa na babban tashar jiragen ruwa. Ƙarƙashin wuta da ƙona turare, da kuma sarrafa shayi da taba, muhimman sana'o'i ne a cikin mulkin mallaka a wannan lokacin. Kasar Portugal ta sami damar cin gajiyar raunin kasar Sin bayan yakin da kuma tabbatar da ikonta; Gwamnan Macau ya fara kin biyan kasar Sin kudin haya na shekara-shekara don mulkin mallaka a cikin shekarun 1840, kuma ya hade Taipa da Coloane, a cikin 1851 da 1864 bi da bi. Portugal kuma ta mamaye Lapa da Montanha da ke kusa, amma za a mayar da su zuwa China a shekara ta 1887, lokacin da aka ba da haƙƙin mallaka na har abada a kan Macau a cikin Yarjejeniyar Peking ta Sin da Fotigal. Wannan yarjejeniya kuma ta hana Portugal daga barin Macau ba tare da amincewar kasar Sin ba. Duk da rikice-rikice na lokaci-lokaci tsakanin hukumomin Cantonese da gwamnatin mulkin mallaka, matsayin Macau bai canza ba ta hanyar juyin juya halin jamhuriya na duka
Portugal a 1910 da kuma China a 1911. Kuomintang ta kara tabbatar da ikon mallakar Fotigal a Macau lokacin da aka sake tattauna yarjejeniyar Peking a 1928.