Abstract: Solar flares and coronal mass ejections（CMEs）are the source disturbances of space weather. The type Ⅱ solar radio burst is the result of electromagnetic radiation caused by CME driven shock moving in corona and interplanetary space. Based on the study of solar physics and space weather forecast, the spectrum characteristics and physical causes of type Ⅱ radio burst, especially VLF type Ⅱ solar radio burst, are analyzed, it shows that VLF type Ⅱ solar radio burst can not only be used to estimate the velocity of CME shock, diagnose the coronal magnetic field, but also provide reference for space weather forecast. The research results can provide useful reference for the scientific research of space VLF radio observation equipment.