My father just passed away and I am wondering that when I get to heaven will we know each other as we were on earth?
I am very sorry to hear of your loss. I am sure however that it is a comfort to you to have a faith in Jesus and a knowledge that we can be reunited with our loved ones.
There are several passages in the Bible that give us comfort in this regard.
Firstly, you will note that Jesus Christ, as the "First fruits" of the resurrection, was recognised and worshipped by the disciples. When Mary at the tomb and the disciples on the road to Emmaus did not recognise him, it was because they were not expecting to see him. Mary recognised him as soon as he spoke to her (John 20:16). The disciples, including Thomas rejoiced in his presence (Vs 19-29). They were then able to renew and continue the relationship they had with him before his death.
The apostle Paul writes about what we will be like following the resurrection. and what we will be like in 1 Corinthians 15:42 and following. In these verses it is clear that our feeble mortal bodies that deteriorate with age and suffer from illness and physical damage will be replaced with immortal, vibrant bodies that will last us for eternity. The most important verses are 51-54:
"Listen, I tell you a mystery: We will not all sleep, but we will all be changed-- in a flash, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, the dead will be raised imperishable, and we will be changed. For the perishable must clothe itself with the imperishable, and the mortal with immortality. When the perishable has been clothed with the imperishable, and the mortal with immortality, then the saying that is written will come true: "Death has been swallowed up in victory.""
What we have then will be better than what we have now. Sure, we will recognise each other. Our characters, our memories, our affections will be the same. That is why in 1 Thessalonians 4:18 Paul can say to the members that Jesus second coming and the resurrection and good news for those who have lost family members, that we can "comfort one another with these words".
I do not know exactly what heaven is going to be like. I rejoice that I can be there with my Saviour and God. I rejoice that I can be reunited with loved ones. But there is one more promise that I hold as very precious. 1 Cor. 2:9:
"No eye has seen,
no ear has heard,
no mind has conceived
what God has prepared for those who love him"
That is something I can look forward to.