I'll stay at Venetian Hotel. Is there any free shuttle bus to bring me to sightseeing around macau?

I am sorry that there is no free shuttle buses to these places. You may travel by bus instead.

To the temple: take bus line MT4 from Est. Baia N. S. Esperanca/ Galaxy Station to the temple. The fare is MOP 4.2.

To Ruins of St. Paul's: take bus line 26A from Est. Baia N. S. Esperanca/ Istmo Station to Almeida Ribeiro/ Weng Hang Station. The bus fare is MOP 4.2. Then, walk north for about 550 yards to the attraction.

To the tower: take bus line MT1 from Est. Baia N. S. Esperanca/ Istmo Station to Praca Ferreira Amaral Station for MOP 4.2. Then, change to bus line 9A to the tower for MOP 3.2. :)