1.intranet is used in an single organisation while the internet are used in world wide web.In intranet if me and you want to access the information of any company or university and you can take any example of big organisation so it is not possible to access any information about the company by us.If we want to access the information about any organisation so we first of all athenticate to that company for access the data then you can access the data from an particular organisation.
2.intranet can access the internet but the internet cannot be access the intranet.
3.Intranet provide security to much higher than internet because internet are access by any person from anywhere any anytime but the Intranet can access by only the person of that organisation.