The invention provides a time series data online compression method supporting editing. One data block serves as a basic storage unit, time series data are decomposed into time series value groups and mass groups, and the time series value groups and the mass groups are compressed and stored at the heads and the tails of the data blocks till the groups are fully stored in the data blocks. Under the condition that time series data mass is stable, the time series data of the digital quantity type only occupy 4 bytes of storage space, floating point values are further compressed, the time series data of the analog quantity type only occupy 6 bytes of storage space, and therefore the data size is obviously reduced and system performance is improved. Each original datum corresponds to a storage method of a time series value group, the compressed and stored data can support fast editing modification.