Instructions
Go to Fuchsia City, located west of Route 15 and east of Route 18. In Fuchsia City, walk north as far as possible, then enter the building surrounded by a fence.
Pay the cashier $500 to enter the Safari Zone. You receive 30 Safari Balls. If you use all the Safari Balls or take 600 steps in the Safari Zone, you are forced to leave. Get back inside by paying the entry fee again.
Head to Area One or Area Three. Each Area is marked with a sign by the entrance. Walk around in grassy spots to lure Pokemon towards you. If any Pokemon other than Kangaskhan appears, run away from it.
Keep walking until Kangaskhan appears. Throw some bait to distract Kangaskhan. While she eats, throw a Safari Ball to catch her. If she breaks out of the Safari Ball, she will probably flee from you. If so, find her and try catching her again.