Abstract: The present invention relates to a new type pyrazolopyrimidine compound, a composition thereof, a preparation method therefor and the use thereof as an anti-cancer drug having anti-tumor activity. The new type pyrazolopyrimidine compound has structural general formula (I) as shown below, is used as an ATR inhibitor, has a good tumor inhibition activity, high selectivity, good water solubility and low toxicity, and can be used for oral administration or intravenous injection administration.