But the NASUWT defended some of the bill's proposals, which it said would help teachers discipline pupils.
Mary Bousted, general secretary of the Association of Teachers and Lecturers, was among the harsher critics of the plans, which include creating new semi-independent trust schools. "Working-class parents and children will find nothing in the education bill which will help them to achieve more from the state education system," she said.
Similiar criticisms will be made this weekend at the National Union of Teachers conference in Torquay. A motion by the union's executive says the bill's proposals will "break up the coherent provision of maintained education" in England and threaten teachers' pay and working conditions.
It says that the Government's promotion of "choice and diversity between schools will create fundamental inequities in the educational opportunities available to children" and may lead to covert selection.
In contrast, the NASUWT praised aspects of the bill in an emergency motion.
Its national executive said teachers would welcome legislation giving them a clearer right to discipline pupils inside and outside their schools.
Chris Keates, NASUWT general secretary, said: "The positive sides of the bill have been overlooked. We know of members who have been terrorised in their own homes and been the subject of internet abuse - so being able to discipline pupils off-site is an extremely positive development."
The union also applauded the bill's proposals to give local authorities greater powers to intervene in schools which were breaking rules governing teachers' working conditions.
However, it joined the other unions to criticise plans to create trust schools, which may be overseen by businesses or charities.