Hi MrYu,
your circuit should work well if you use appropriate power supplies for both, the low voltage and the mains voltage part.
Using any phantasy-power source won't suffice for a successful simulation. Select an AC power source for proper simulation.
You might also use a proper device to simulate the LDR with light source.
Your circuit wastes one transistor!
You have two options to reverse action by putting the LDR from the base towards ground or from the base towards the positive rail of the device.
Have a look at my simulation results, one with the light bulb on and the other one with it off.
Boncuk