Shanghai, managed by former England boss Sven-Goran Eriksson, broke the record of £38.4m that Jiangsu Suning paid for compatriot Alex Teixeira.
Hulk, 29, scored 21 goals for Russian side Zenit last season.
Chinese clubs spent almost £200m in the most recent transfer window.
Hulk, who played for three Japanese clubs before moving to Porto in 2008, signed for Zenit for £32m in 2012.
He joins former Sunderland striker Asamoah Gyan at Shanghai.
Runners-up in the CSL last season, Shanghai are currently fourth in the table.
The Chinese Football Association announced plans in March to become a "world football superpower" by 2050.
The national team - 81st in the Fifa rankings- have qualified for the World Cup only once, in 2002.
Eriksson, who coached Guangzhou R&F before joining Shanghai in 2013, has said the league's growth will attract "even bigger names".
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Brazil forward Hulk has become the most expensive signing in Asian football with a £46.1m (55.8m euros) move to Chinese Super League side Shanghai SIPG from Zenit St Petersburg.