The object of the present paper is to study Quasi-concircularly flat and $\phi-$quasi-concircularly flat generalized Sasakian-space-forms. Also, we consider generalized Sasakian-space-forms satisfying the condition $P(\xi, X).\widetilde{V}=0,\ \widetilde{V}(\xi, X).P=0, \ $ and $\widetilde{V}(\xi, X).\widetilde{V}=0$ and we obtain some important results. Finally, we give an example.