Seamus Searson will outline criticism of the measures contained in the Scottish Government's new Education Bill on the opening day of the Scottish Secondary Teachers' Association (SSTA) annual congress.
He will also use his speech to highlight recurring issues around workload, pay and teacher shortages.
Mr Searson will tell members proposed changes contained in the SNP administration's latest legislation are not welcomed by the majority of the public.
The Bill would see sweeping reforms to the school system, including the introduction of a new Headteachers' Charter, giving heads more power over the curriculum, recruitment and budgets.
Mr Searson will say: "The creation of a Headteachers' Charter is unwanted by many headteachers as they are already struggling to cope with all the demands placed upon them.
"There is no public consensus for this so minister don't proceed."
He will also criticise plans to disband the General Teaching Council of Scotland (GTCS) and transfer its functions to a new Education Workforce Council - a move described by the GTCS as having "no evidence-based rationale".
He will add: "The priority must be to make changes that are going to help the teacher in the classroom today.
"If the proposed Education Bill is not going to help teachers in the classroom today then don't do it.
"It does not address the issues that are important to teachers today - pay, workload and pupil behaviour."
The SSTA says teachers' pay has fallen by almost 19% in the past decade when inflation and increased national insurance and pension contributions are taken into account.
Meanwhile, the union says workload has increased and called for a national qualifications system "without the workload heavy, bureaucratic and administrative nonsense".
Mr Searson will say such issues have resulted in teachers quitting the profession, and difficulty in filling posts.
"Teaching is not attractive when we have low pay, spiralling workload demands and when schools are unable to meet the needs of more demanding and challenging pupils," he will add.
A spokesman for the Scottish Government said: "Our education reforms are focused on giving schools and headteachers more power and money to raise standards and close the attainment gap. They are based on international evidence of how high-performing education systems work - delivering extra help for teachers in the classroom, more professional development and a stronger voice for parents and pupils.
"The majority of respondents to the consultation support the principles behind our education reforms and, as the International Council of Education Advisers said last month, the direction of travel in Scottish education is impressive. They also welcomed the recent establishment of Regional Improvement Collaboratives.
"We are giving careful consideration to the feedback on the Education (Scotland) Bill and will set out our next steps in due course."