BICEP2 claimed they discovered signals about primordial gravitational waves in March this year. Some astronomers and cosmologists questioned that whether the signal is from primordial gravitational waves or galaxy dust. Planck released dust map of in September, but further result will be released till next month. I will talk about the cosmological constraint on primordial gravitational waves with results of BICEP2 and prior of dust from Planck dust map, which indicates that there’s no large B-mode signal.