At every particular time in the evening, my car temperature rise even when the is blowing. And I have worked on the thermostat. What next should I do

Check your coolant level, could just be low...next would be replace the thermostat...Hope this helps.

Flush the radiator?

You need to get the engine full of coolant. Air is trapped in system. Use bleed valve

Sounds like you have a stuck thermostat. New or not, thermostats can get stuck.

yes first place to start usualy gets stuck open or close in your case it seems to be open.

With the truck running at operating temperature, squeeze your upper radiator hose. You may have to check it a couple times allowing time for your thermostat to open. Are you able to compress the hose a little when you squeeze it or does it remain stiff/solid? Your thermostat may be stuck open or even stuck closed.

Check to make sure your thermostat works right by monitoring the warming up of your engine. With a completely cold engine, start and run the engine for a few minutes, then put your hand on the top radiator hose to monitor if and when it gets warm as the thermostat opens more and more and note the gauge reading( if it works) the top radiator hose should be unbearably hot within 5-8 minutes. If the therm. opens right it should close right aswell, staying open a little while eventhough the radiator may have cooled may be what you are experiencing causing the rapid cooling and is nothing to worry about. The Hose should not get warm very soon after starting the engine. Regarding you gauge, lets take one step at a time, verify proper op. or the therm.

Yes,it rules it out. The valve leading the water into the heater core is not opening or the door that put the air past or through the heater core is closed. This is general information not specific to your particular model.

It could be very well your water pump from the sounds of it. When was the last time you had that check or replaced? That would be my next guess to the problem...what's your mileage on the car?

there is a valve on the water pump and one on the thermostat housing open those up one at a time until you get a little bit of antifreeze come out then tighten them back up. All you will be doing is bleeding the air out of the cooling system. my car was doing the same thing after I changed my thermostat.