What is the meaning of spots of blood in panty when i am wearing it?

It could be one of three things.

#1 ; An-al fissure / haemorrhoids(piles).

#2 ; urinary tract infection, in which case urinating can be very frequent and painfull.

#3 ; You don't say how old you are, but if a girl of approximately 9 - 15 years of age, it could be the menarche(starting your periods).

In any case go and see a doctor to identify the problem.