Here on this world, we can have only analogous (analogy of proper proportionality) knowledge of God. When someone attains the beatific vision, does he have univocal knowledge of God? If not, is knowledge attained in beatific vision analogous also? Please explain your answer.
is direct knowledge of God
The Beatific Vision is not analogical knowledge but immediate (i.e., "with no intermediary") knowledge; it's direct, intuitive, non-discursive knowledge.
Pope Benedict XII's 1334 edict Benedictus Deus "On the Beatific Vision of God" says the blessed
see the divine essence with an intuitive vision and even face to face, without the mediation of any creature by way of object of vision; rather the divine essence immediately manifests itself to them, plainly, clearly and openly, and in this vision they enjoy the divine essence.
vident divinam essentiam visione intuitiva et etiam faciali, nulla mediante creatura in ratione obiecti visi se habente, sed divina essentia immediate se nude, clare et aperte eis ostendente, quodque sic videntes eadem divina essentia perfruuntur
However, this does not mean it is exhaustive, all-comprehensive knowledge of God. Only the Persons of the Holy Trinity know themselves exhaustively/infinitely. See St. Thomas Aquinas, Summa Contra Gentiles III q. 55 "That the created intellect does not comprehend the divine substance".
requires light of glory (lumen gloriæ)
The Council of Vienne (Denz. 475) condemned the proposition:
That any intellectual nature in its own self is naturally blessed, and that the soul does not need the light of glory raising it to see God and to enjoy Him beatifically.
Quod quaelibet intellectualis natura in se ipsa naturaliter est beata, quodque anima non indiget lumine gloriae, ipsam elevante ad Deum videndum et eo beate fruendum.
Thus, we cannot attain the Beatific Vision with our own natural human reason.
In SCG III, St. Thomas shows that "human felicity does not consist in the knowledge of God gained through demonstration" (q. 39) and even that "Human felicity does not consist in the knowledge of God which is through faith" (q. 40)!
A good overview of all this is ch. 29, "The Sublimity of the Beatific Vision," of Life Everlasting by Fr. Réginald Garrigou-Lagrange, O.P. He mentions analogical knowledge in ¶2, § "This Vision Is Intuitive and Immediate":
By its clarity this vision is distinguished from the obscure knowledge which we have of God, either by reason or by faith. By its intuitive and immediate character it is immeasurably superior to all knowledge that is discursive and analogical, which does not reach God except by using His effects as principle. This intuitive vision is higher than all abstraction, all reasoning, and all analogy. It is immediate intuition of the supreme reality of the living God. Hence it surpasses by far all vision, even the intellectual visions which the great mystics receive here on earth, because these visions remain within the order of faith and do not give intrinsic evidence of the Trinity. The beatific vision, on the contrary, does give this evidence, showing that God, if He were not triune, would not be God.