Based on the dynamic monitoring data of China's migrant population(2014),an empirical analysis of the"income premium"effect of labor union on migrant population is made.The study finds that labor union can significantly increase the income of the migrant population.However,the"income premium"effect of labor union is obviously heterogeneous.The urban migrant population is higher than the rural migrant population,and the contract signing ratio is higher than those who have not signed a contract,and private companies outperforms state-owned collective enterprises and foreign-funded enterprises.Th...