With the universal use in the all walks of life，the big data has show its abuse gradually. This paper chose the 2016 election in the united states as background，chose the opinion polls the media institutions hold which predict Hillary Clinton will won and the Poll Results which actually show the victory of Donald Trump as the subjects，aiming to explore the reason which caused the significant contrast between this prediction and reality，based on the massive data analysis of big data news and actual outcome. Furthermore，the influence of big data news predictive application on journalistic objectivity.