There is no any particular book for the preparation, it is advisable to revise your 11th-12th syllabus properly and once it is done, start doing previous year papers as these will be helping you to know difficulty level of questions along with paper pattern. You can download the previous year papers with the given below link.

http://bhuonline.in/old-qus-paper-entr.html

Good Luck!

Hello Dheeraj,

You can follow the NCERT, RD Sharma or BHU B.SC Math Group Entrance Exam 2018 by Arihant Experts etc. to prepare for BHU B.Sc. mathematics entrance exam.

Hope these prove beneficial to you!

Good Luck!