Hello Dear,

No, syllabus do not change every year in UPSC. UPSC has a very vast syllabus. It is said that every thing under the Sun is its syllabus. Actually its the pattern which changes every year. Since 2011 there no change in syllabus of UPSC CSE, only change is Prelims paper 2 was made qualified in 2014. UPSC changes it's way of asking questions and follows different pattern every year. Try to read everything what is there in syllabus. Read, revise and apply is only thing we have do to crack this exam.  For more information you can visit the link below:

https://competition.careers360.com/exams/upsc-civil-services-exam

Good Luck