I wanted to Know where is the Convenant Box? In Most Holy Place There was Convenant Box but is it still there?
I assume you mean the "Ark of the Covenant".
Shekalim 6: Mishnah 1: There were thirteen horn-shaped chests,' thirteen tables, and thirteen prostrations in the Temple. Those of the House of Rabban Gamaliel and they of the House of R. Chanania the Prefect of the priests used to prostrate themselves fourteen times. And where was the extra one? '-Opposite the woodstore, for thus was a tradition among them from their ancestors that the Ark was hidden there.'
Mishnah 2: It happened once that a certain priest was occupied and noticed that some flooring- was different from the rest. He went and was telling it to his fellow, but before he could end the matter his soul was departed from him.' And thus they knew definitely that there the Ark had been hidden.
From the Rambam (Maimonides) Mishneh Torah or Sefer Yad ha-Hazaka, Hilchot Beit HaBechirah, 4:11:
"The Ark was placed on a stone in the western portion of the Holy of Holies.nThe vial of manna and Aharon's staff were placed before it.
When Solomon built the Temple,he was aware that it would ultimately be destroyed. [Therefore,] he constructed a chamber, in which the ark could be entombed below [the Temple building] in deep, maze-like vaults.
King Josiah commanded that [the Ark] be entombed in the chamber built by Solomon, as it is said (II Chronicles 35:3): "And he said to the Levites who would teach wisdom to all of Israel: 'Place the Holy Ark in the chamber built by Solomon, the son of David, King of Israel. You will no [longer] carry it on your shoulders. Now, serve the Lord, your God.'
When it was entombed, Aharon's staff, the vial of manna, and the oil used for anointing were entombed with it. All these [sacred articles] did not return in the Second Temple."