Hai, Where I can get into sightseeing ferry in Huangpu River? Thank you.

You can take the sightseeing boat at Shiliupu Pier, No.481, East Zhongshan 2nd Road. In addition, there are several places for you to purchasing the tickets:
No.479, East Zhongshan 1st Road (nearby Garden Bridge );
No.341, East Zhongshan 1st Road (nearby Nanjing Road);
No.129, East Zhongshan 2nd Road (nearby Jinling Road);
No.141, East Zhongshan 2nd Road (nearby Jinling Road);
No.153, East Zhongshan 2nd Road (nearby Jinling Road);
No.241, East Zhongshan 2nd Road (nearby Jinling Road);
Hope helpful!