First of all, because of the unlimited supply of labor, migrant workers stay in a long-term lower level of payment,whose labor are cheap . Second, migrant workers can not enjoy the same social protection and social welfare compared with urban workers , , to reduce labor costs.in these areas furtherly First of all, because of the unlimited supply of labor, migrant workers stay in a long-term lower level of payment,whose labor are cheap . Second, migrant workers can not enjoy the same social protection and social welfare compared with urban workers , , to reduce labor costs.in these areas furtherly