The zoo is at University Town station. So from Luohu (green line), I would go north to Laojie. Then change to go further north to Buji (blue line). At Buji, change and go west to University Town (violet line). It will take you about 45 mins to get there from Luohu. When you reach University Town, use Exit C (stay on the road side of the exit) and go North on Lishan Road (i.e. go right at Exit C) until it ends at Lishui Road, then left/west short distance until it ends at Xili Road and finally go right/north a short distance and the entrance will be on the right/east of the street. It is about 1.4km walk (another 20 mins). There will be brown direction signs to the park at the level of street lights i.e. above your head. So plan your journey well knowing that you would want to be there as early as possible so that the kids can enjoy all the animals and also see the shows without being in a hurry i.e. you can sit at times and rest. There are other attractions inside the zoo for kids and adults e.g. inflatable balloon on the lake (kids love it), getting on elephant's back, the dolphins show, feed the bears. Some are free but others are for a small fee like 10 or 20 yuans. But well worth them if this is the first time to a big zoo. I also suggest doing the visit on foot rather than by mini bus. you can then take all your time. Enjoy.