space marines plus grey knights 1500 pts army.

HQ: space marine Chaplain in terminator armour with combi-plasma. 135 pts.
HQ: grey knights grand-master with 5 Grey Knight terminators including 1 with psycannon. 435 pts. Grand-master has hammerhand, storm shield, master-crafted nemesis force weapon and terminator armour.
Troops: 1 unit of 1 justicar with master-crafted nemesis force weapon plus 9 grey knights including 1 with incinerator. 340 pts. Justicar has melta bombs. Rhino with hunter-killer missile.
Troops: 1 unit of 4 space marine scouts with sniper rifles, plus sergeant Telion. 125 pts.
Fast Attack: 3 Space Marine Land speeders. 1 with heavy flamer. 150 pts.
Heavy support: space marine dreadnought. 145 pts. Heavy flamer, Twin-linked lascannons.
Heavy support: Space Marine devastator squad with five members. 170 pts. 1 lascannon, 1 with heavy bolter. Sergeant with plasma pistol.
pts = 1500
I hope it's good.

If I'm not mistaken, you need to have the minimum 2 Troops choices from your parent list, meaning you need to get another SM troops choice

HQ: space marine Chaplain in terminator armour with combi-plasma. 135 pts.
HQ: grey knights grand-master with 5 Grey Knight terminators including 1 with psycannon. 435 pts. Grand-master has hammerhand, storm shield, master-crafted nemesis force weapon and terminator armour.
Troops: 1 unit of 1 justicar with master-crafted nemesis force weapon plus 9 grey knights including 2 with incinerator. 350 pts. Justicar has melta bombs. Rhino with hunter-killer missile.
Troops: 1 unit of 4 space marine scouts with sniper rifles, plus sergeant Telion. 125 pts.
Troops: 5 tactical space marines. Sergeant with plasma pistol. 105 pts.
Heavy support: space marine dreadnought. 145 pts. Heavy flamer, Twin-linked lascannons.
Heavy support: Space Marine devastator squad with five members. 205 pts. 2 lascannons, 1 heavy bolter. Sergeant with plasma pistol.
1500
ok here's the fixed one

please rate!! brothers

You should give the rhino to the tactical marines because the space marine rhino is cheaper and better and it isn't dedicated to one unit. And GK's can't take transports. That's just the first thing I notice.

HQ: space marine Chaplain in terminator armour with combi-plasma. 135 pts.
HQ: grey knights grand-master with 5 Grey Knight terminators including 1 with psycannon. 435 pts. Grand-master has hammerhand, storm shield, master-crafted nemesis force weapon and terminator armour.
Troops: 1 unit of 1 justicar with master-crafted nemesis force weapon plus 9 grey knights including 2 with incinerator. 350 pts. Justicar has melta bombs.
Troops: 1 unit of 4 space marine scouts with sniper rifles, plus sergeant Telion. 125 pts.
Troops: 5 tactical space marines. Sergeant with plasma pistol. 105 pts. Rhino with hunter-killer missile.
Heavy support: space marine dreadnought. 145 pts. Heavy flamer, Twin-linked lascannons.
Heavy support: Space Marine devastator squad with five members. 205 pts. 2 lascannons, 1 heavy bolter. Sergeant with plasma pistol.
1500

ok better now?

Well you should try it out a few times and see how it works for you.

I'd say that the plasma pistols are quite worthless on your squad sargents.Sure they can thin out the enemy squad,without alloing them any saves,but they can also kill your sargent and it wouldn't make a lot of difference unless your enemy is something with terminator armour like SM,CSM or GK terminators,ork Mega-Nobs and the like.But if the one would consenctrate theyr terminator and the like at your devastators,then I'd say that they would be stupid or they had all ready killed off everýthing else.Plus that signum that you have on your Dev.Sarge is usefull,even if it only gives one of your special weapon guys the chance to hit with 2+ instead of 3+.I'd say that if you really want plasma to take care of the enemy,take off the plasma pistols and try and take a plasma cannon for your dev squad.