SecureClient can not reach office PCs

SecureClient can not reach office PCs which has not been configured with default gateway.

Such as the checkpoint internal IP addres: 10.10.10.254, which will be used as office PCs default GW.

If the secureclient can reach the office PCs which has been configured with deault gateway (10.10.10.254).

But SecureClient can not reach office PCs which has not been configured with default gateway.

If I understand your scenario correctly then I think you will need the default gateway configured on your PCs if SecureClient is to work. A VPN by definition needs to be a tunnel between two endpoints and usually the endpoints have to be on differing IP networks to allow your traffic to be routed down the tunnel. Because of this your PCs will need to know the address of the Checkpoint box as the gateway to devices not on the same IP network as themselves.