1. Pressure groups donot contest elections whereas political parties contest elections.
2. Pressure groups donot aim directly to control or share power whereas political parties aim to directly control or share political power.
3.Pressure groups are formed when people with common occupation , interests, aspirations or opinions come together inorder to achieve a common objective whereas political parties agree on some policies and programmes for the society with a view to promote the collective good.
pressure groups are the groups which do not take part directely in politics but can influnce the major plicies made by govt.and they have tight organisation.
political parties are group of people who contest elections and form govt. they directely take part in politics.