Can I take bus from forbidden city north gate exit to Bei Hai park South Gate ? which bus ?

But it is so close. No need to bother to catch a bus at all! After getting out from the north gate of Forbidden City, walk along Jingshan Qianjiefor around 250 meters and turn into Jingshan Xijie. Continue to move forward for about 270 meters and turn left to Zhishanmen Jie to find the entrance of the park.