how can i stop my child from catnap   

It is a good thing that a child takes a nap. You may feel nap time interferes with bedtime, but well-rested kids quicker settle down at night than overtired ones. Well-rested kids sleep well all through the night. To get asleep that makes them feel rested, babies need at least 45 minutes of sleep. So it's okay if your baby takes a nap for 45-60 minutes. If it exceeds, you can wake them up and plan their day with activities or play. If they have nothing to do, they will get bored and will feel sleepy. Also, every child has different bodily needs, so if your baby is growing fine, achieving all milestones, is physically active, sleeps well at night, does not become lazy, and eats well, do not worry about sleep. Let them sleep peacefully.