Fortunately, thanks to comments and suggested link of @user2339071, I could solve the problem:
If you are using Windows OS, you must replace ":" with ";". So, this code worked for me:
C:\mallet> java -cp "C:\mallet\class;C:\mallet\lib\mallet-deps.jar" cc.mallet.fst.SimpleTagger --model-file G:\test1-model G:\test2-feats.txt
Actually, what is done with this code is that two different paths are determined as the classpath, one is the folder which includes .class files of mallet (C:\mallet\class) and the other one includes all required jar files (C:\mallet\lib\mallet-deps.jar) and you need to separate them with ";".
That's all!