To produce useful information about the raw materials used in northern Chinese Yaozhou celadon glazes Chinese glazes (especially the source of the calcium‐bearing flux), Sr isotope analysis has been used for the first time. Yaozhou celadon is one of the most important representatives of northern Chinese greenware. The study has enhanced our understanding of the raw material sources used to make Yaozhou glazes dating from the Tang to Northern Song dynasties. It is highly likely that ‘Fuping stone’ mentioned in the historical record is not the main raw material used to make Yaozhou celadon glazes of the Tang to Northern Song dynasties. The results of 87Sr/86Sr analysis of the Yaozhou celadon glazes studied produce relatively consistent 87Sr/86Sr isotopic signatures, with a wide variation of relatively high Sr concentrations. This is firm evidence that a calcium‐bearing plant ash was the source of the calcium and of the flux in the Celedon glazes studied, and not, as some have suggested, limestone or ‘Liaojiang stone’. The study had illustrated that the present approach has great potential in providing a new way of reconstructing porcelain glaze technology.