Everyday has several ferryboats between Putuoshan and Shanghai.
Transportation options:
Shanghai-Putuoshan: From the Shanghai Shiliepu Harbour near the Bund, the main passenger harbour of Shanghai, there are 8AM buses to transfer you to Luchaogang Harbour where a fast boat to Putuoshan is available. It costs RMB156 per person for a soft seat on the boat (bus fare included) and the trip takes three and a half hours.
Putuoshan-Shanghai: Take the night boat which departs from Putuoshan every day at 16:30pm. The boat arrives in Shanghai the next morning around 6am. Second class beds costs RMB163.