It gives them the chance distinguish themselves from other students with similar qualifications.
Ucas head of technology and strategy Steve Harrop said: "A personal statement should be the student's own work.
"The new system, Copycatch, will compare every application submitted for entry next year with thousands posted on websites and 1.5 million from previous years."
If three sentences or more - 10% of the statement - appear to have been copied, the form will be passed to Ucas staff for further scrutiny.
They might then pass the case on to the individual institutions to which a student has applied for a decision on further action.
Cut and paste
Ucas said checks on 50,000 forms earlier this year found that approximately 5% of applications had "some element of plagiarism".
This ranged from a very low level through to candidates who had copied and pasted the whole thing.
Mostly students appeared to use material from websites offering advice on how to apply.
Analysis for Ucas showed some 800 would-be medical students had lifted chunks of text from the same website.
And 234 included the same anecdote saying their interest in chemistry had begun when they had burnt a hole in their pyjamas.
As the deadline for applications got closer the number of those using borrowed material had increased, the study found.
When the results of this research was received, Ucas said it would be looking at how it could screen applications for similar borrowed material.
