In the theory of risk society，the paper analyses the four-dimensional dilemmas the mass media are facing，which can mainly be found in the plight of mass media between work rationality and value rationality，the gap on its roles realized in society，the difficulty to balance and the external pressure.All these difficulties have so much influence on media that the positive effects are usually weakened，even been transfered into negetive effects. The article argues that in order to avoid the risk，the government，the expert，the media and the public should be positive communication and reflection to avoid the risk.