I am from India to China Pek CA948 at t3 and then dep to Vancover CA997 please tell.

It is an international to international transfer. You need to have your passport stamped at Immigration Desk. You needn't go to Air China Check in Counters. There are international transfer counters on 3F, T3-E.

Here are the procedures for your reference: Flight Arrival- Transfer Procedures- Immigration Inspection- Security Check- Customs Inspection- Waiting& Boarding. :)