The decision has been taken on the ground of sovereignty as India considers POK its part.
Christened as China Pakistan Economic Corridor, the 57 billion-dollar project envisages connectivity across Asia on to Europe through ports, railways and roads.
Besides Pakistan, India's other neighbours Sri Lanka and Nepal are attending the summit.
The US too has decided to attend, marking a U-turn in its position, NDTV says.
Earlier this week, External Affairs Ministry spokesperson Gopal Baglay said India supports connectivity across the region, but there is a problem with the Pakistan end of "One Belt, One Road" (OBOR). .
"As far as OBOR is concerned, you know that our position is that since the so-called CPEC forms a part of OBOR, that is where our difficulty is," he said.
"It passes or proposes to pass through what is sovereign Indian territory and we have made our views in this regard very, very clear to the Chinese side."
The Chinese initiative is also being seen as a move to establish its dominance in Asia, including India's neigbhours.