Where is the nearest subway in prospect park Brooklyn ny ?

The Q stops at Prospect Park and the 2/3 stops at Grand Army Plaza

There's several. The park is huge and your choice depends on the place in the park you wish to visit first. Use the 'Transit' layer on Google Maps to find all nearby stations. They are served by the 2, 3, 4, 5, B, Q, F G lines.

You can take the south bound F train to 15 Street prospect park west train station.

Can take the F at 7ave