What is better after diploma in mechanical engineering Job or Degree?

Dear Ataur, As a friend I would suggest you to go for degree as diploma will fetch you a decent job but would restrict your future growth. Also, the basic eligibility in most of the corporates is graduation. Thus the better option is opting for graduation after diploma. As you have already done a

You can't good job on the basis of your diploma even if you do a job after diploma you will have pursue degree in future if you want better post therefore it is better to do it now and then do a job after getting a degree

You have to go for engineering degree for good job prospectus